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1.
BMC Plant Biol ; 21(1): 183, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33863284

RESUMO

BACKGROUND: PROTEIN PHOSPHATASE 2A (PP2A) expression is crucial for the symbiotic association between plants and various microbes, and knowledge on these symbiotic processes is important for sustainable agriculture. Here we tested the hypothesis that PP2A regulatory subunits, especially B'φ and B'θ, are involved in signalling between plants and mycorrhizal fungi or plant-growth promoting bacteria. RESULTS: Treatment of tomato plants (Solanum lycopersicum) with the plant growth-promoting rhizobacteria (PGPR) Azospirillum brasilense and Pseudomonas simiae indicated a role for the PP2A B'θ subunit in responses to PGPR. Arbuscular mycorrhizal fungi influenced B'θ transcript levels in soil-grown plants with canonical arbuscular mycorrhizae. In plant roots, transcripts of B'φ were scarce under all conditions tested and at a lower level than all other PP2A subunit transcripts. In transformed tomato plants with 10-fold enhanced B'φ expression, mycorrhization frequency was decreased in vermiculite-grown plants. Furthermore, the high B'φ expression was related to abscisic acid and gibberellic acid responses known to be involved in plant growth and mycorrhization. B'φ overexpressor plants showed less vigorous growth, and although fruits were normal size, the number of seeds per fruit was reduced by 60% compared to the original cultivar. CONCLUSIONS: Expression of the B'θ gene in tomato roots is strongly influenced by beneficial microbes. Analysis of B'φ overexpressor tomato plants and established tomato cultivars substantiated a function of B'φ in growth and development in addition to a role in mycorrhization.


Assuntos
Azospirillum brasilense/fisiologia , Lycopersicon esculentum/genética , Micorrizas/fisiologia , Proteínas de Plantas/genética , Proteína Fosfatase 2/genética , Pseudomonas/fisiologia , Simbiose/genética , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/microbiologia , Proteínas de Plantas/metabolismo , Raízes de Plantas/microbiologia , Proteína Fosfatase 2/metabolismo , Transcrição Genética
2.
Planta ; 253(4): 78, 2021 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-33715081

RESUMO

MAIN CONCLUSION: The in vitro application of rhizosphere microorganisms led to a higher rooting percentage in Pyrus Py12 rootstocks and increased plant growth of Pyrus Py170 and Prunus RP-20. The rooting of fruit tree rootstocks is the most challenging step of the in vitro propagation process. The use of rhizosphere microorganisms to promote in vitro rooting and plant growth as an alternative to the addition of chemical hormones to culture media is proposed in the present study. Explants from two Pyrus (Py170 and Py12) rootstocks and the Prunus RP-20 rootstock were inoculated with Pseudomonas oryzihabitans PGP01, Cladosporium ramotenellum PGP02 and Phoma sp. PGP03 following two different methods to determine their effects on in vitro rooting and plantlet growth. The effects of the microorganisms on the growth of fully developed Py170 and RP-20 plantlets were also studied in vitro. All experiments were conducted using vermiculite to simulate a soil system in vitro. When applied to Py12 shoots, which is a hard-to-root plant material, both C. ramotenellum PGP02 and Phoma sp. PGP03 fungi were able to increase the rooting percentage from 56.25% to 100% following auxin indole-3-butyric acid (IBA) treatment. Thus, the presence of these microorganisms clearly improved root development, inducing a higher number of roots and causing shorter roots. Better overall growth and improved stem growth of treated plants was observed when auxin treatment was replaced by co-culture with microorganisms. A root growth-promoting effect was observed on RP-20 plantlets after inoculation with C. ramotenellum PGP02, while P. oryzihabitans PGP01 increased root numbers for both Py170 and RP-20 and increased root growth over stem growth for RP-20. It was also shown that the three microorganisms P. oryzihabitans PGP01, C. ramotenellum PGP02 and Phoma sp. PGP03 were able to naturally produce auxin, including indole-3-acetic acid (IAA), at different levels. Overall, our results demonstrate that the microorganisms P. oryzihabitans PGP01 and C. ramotenellum PGP02 had beneficial effects on in vitro rooting and plantlet growth and could be applied to in vitro tissue culture as a substitute for IBA.


Assuntos
Cladosporium/fisiologia , Raízes de Plantas/fisiologia , Prunus/fisiologia , Pseudomonas/fisiologia , Pyrus/fisiologia , /fisiologia , Raízes de Plantas/microbiologia , Prunus/microbiologia , Pyrus/microbiologia , Rizosfera , Microbiologia do Solo
3.
J Fish Dis ; 44(4): 391-400, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33340371

RESUMO

ß-defensin (BD) is a cysteine-rich cationic antibacterial peptide that is active against a wide range of bacteria. Here, a ß-defensin homolog (LcBD2) was identified in large yellow croaker (Larimichthys crocea). The open reading frame of LcBD2 contains 195 nucleotides, encoding a protein of 64 amino acids that possesses a typical arrangement of six conserved cysteine residues (C31 , C37 , C41 , C53 , C59 and C60 ). LcBD2 transcripts were constitutively expressed in all examined tissues and significantly increased in head kidney, spleen and gills by Vibrio alginolyticus. The synthetic LcBD2 peptide imparted antimicrobial effects on both Gram-negative bacteria (V. campbellii, V. parahaemolyticus, V. alginolyticus, V. harveyi and Pseudomonas plecoglossicida) and Gram-positive bacteria (Bacillus subtilis). We also observed that after treatment with synthetic LcBD2 peptide, numerous blisters appeared on the membrane of P. plecoglossicida, which in turn may result in cell membrane breakage and bacterial death. Moreover, the synthetic LcBD2 peptide significantly upregulated the expression levels of TNF-α2, IL-1ß and CXCL8_L1 in monocytes/macrophages, while downregulated expression level of IL-10. The LcBD2 peptide also remarkedly enhanced the phagocytosis of monocytes/macrophages. These results indicate that LcBD2 not only protects large yellow croaker against multiple bacterial pathogens but also plays a role in activation of monocytes/macrophages.


Assuntos
Doenças dos Peixes/imunologia , Regulação da Expressão Gênica/imunologia , Imunidade Inata/genética , Perciformes/genética , Perciformes/imunologia , beta-Defensinas/genética , beta-Defensinas/imunologia , Imunidade Adaptativa/genética , Sequência de Aminoácidos , Animais , Bacillus subtilis/fisiologia , Doenças dos Peixes/microbiologia , Proteínas de Peixes/química , Proteínas de Peixes/genética , Proteínas de Peixes/imunologia , Perfilação da Expressão Gênica/veterinária , Infecções por Bactérias Gram-Negativas/imunologia , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Infecções por Bactérias Gram-Positivas/imunologia , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/veterinária , Filogenia , Pseudomonas/fisiologia , Alinhamento de Sequência/veterinária , Vibrio/fisiologia , Vibrioses/imunologia , Vibrioses/microbiologia , Vibrioses/veterinária , beta-Defensinas/química
5.
Lett Appl Microbiol ; 71(4): 337-344, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32542738

RESUMO

Aeromonas and Pseudomonas are important bacterial species involved in spoilage of refrigerated freshwater fish. In this study, 10 Aeromonas and seven Pseudomonas bacterial strains were isolated from spoiled grass carp and identified. Twelve of seventeen bacterial strains showed high potential of biofilm formation and 14 of 17 can produce extracellular protease. In order to explore the spoilage capacity of dual-species, the sterile grass carp fillets were inoculated with mono- and dual-species of Aeromonas salmonicida and Pseudomonas azotoformans strains. The results revealed significantly higher levels of the total viable count and total volatile basic nitrogen in dual-species as compared to mono-species from day 6. The higher contents of histamine, cadaverine and serious degradation in muscles tissue were also observed in dual-species after 10 days of storage. Results of in vitro experiments showed that the co-culture of A. salmonicida and P. azotoformans significantly increased the bacterial maximum growth rate, promoted the biofilm formation and improved the spoilage capacity of bacterial strains. This study has revealed that the co-culture of Aeromonas and Pseudomonas bacterial strains accelerated spoilage process of grass carp and increased biofilm formation. It indicates that the mixed-cultures of spoilage micro-organisms pose a huge threat to food industry.


Assuntos
Aeromonas/fisiologia , Carpas/microbiologia , Pseudomonas/fisiologia , Aeromonas/crescimento & desenvolvimento , Animais , Biofilmes , Técnicas de Cocultura , Contaminação de Alimentos/análise , Pseudomonas/crescimento & desenvolvimento
6.
Int J Infect Dis ; 98: 41-50, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32535299

RESUMO

OBJECTIVES: Alternative dosing strategies for ß-lactams - the most common antibiotics used to treat critically ill patients with respiratory tract infections - have been recommended to maximize the duration of exposure and reduce drug resistance. The objective of this study was to evaluate whether extended infusion of antipseudomonal ß-lactams improves mortality and clinical efficacy. METHODS: Two independent authors identified eligible trials by searching the PubMed, Cochrane Library, Scopus, and ICHUSHI databases, in both English and Japanese, up to June 2019. Data were extracted from both randomized controlled and observational trials comparing extended infusion (≥3h) with intermittent infusion in critically ill patients. The primary outcome was all-cause mortality. Risk differences (RD) and 95% confidential intervals (CI) were calculated using a random-effects model and subgroup analyses were performed. Sensitivity and heterogeneity were also evaluated. RESULTS: Nine studies involving 1508 participants were included in the meta-analysis. Mortality was lower for extended infusion than for intermittent infusion (RD -0.10; 95% CI -0.15 to -0.04). However, no significant between-group differences in clinical success, length of ICU stay, length of hospital stay, and antibiotic duration were observed. CONCLUSIONS: Extended infusions of ß-lactams were associated with reduced mortality rates but not with clinical success.


Assuntos
Antibacterianos/administração & dosagem , Estado Terminal/terapia , Infecções Respiratórias/tratamento farmacológico , beta-Lactamas/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Gerenciamento de Dados , Humanos , Bombas de Infusão , Tempo de Internação , Pessoa de Meia-Idade , Pseudomonas/efeitos dos fármacos , Pseudomonas/fisiologia , Infecções Respiratórias/microbiologia , Infecções Respiratórias/mortalidade , Fatores de Tempo , Resultado do Tratamento
7.
Sci Rep ; 10(1): 8196, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32424195

RESUMO

An increasing interest in the development of products of natural origin for crop disease and pest control has emerged in the last decade. Here we introduce a new family of strawberry acyl glycosides (SAGs) formed by a trisaccharide (GalNAc-GalNAc-Glc) and a monounsaturated fatty acid of 6 to 12 carbon atoms linked to the glucose unit. Application of SAGs to Arabidopsis thaliana (hereafter Arabidopsis) plants triggered a transient oxidative burst, callose deposition and defense gene expression, accompanied by increased protection against two phytopathogens, Pseudomonas viridiflava and Botrytis cinerea. SAGs-induced disease protection was also demonstrated in soybean infected with the causal agent of target spot, Corynespora cassiicola. SAGs were shown to exhibit important antimicrobial activity against a wide-range of bacterial and fungal phytopathogens, most probably through membrane destabilization, and the potential use of SAGs as a biofungicide for postharvest disease protection was demonstrated on lemon fruits infected with Penicillium digitatum. Plant growth promotion by application of SAGs was shown by augmented primary root elongation, secondary roots development and increased siliques formation in Arabidopsis, whereas a significant increment in number of seed pods was demonstrated in soybean. Stimulation of radicle development and the induction of an auxin-responsive reporter system (DR5::GUS) in transgenic Arabidopsis plants, suggested that SAGs-stimulated growth at least partly acts through the auxin response pathway. These results indicate that strawberry fatty acid glycosides are promising candidates for the development of environmental-friendly products for disease management in soybean and lemon.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Fragaria/química , Glicosídeos/química , Glicosídeos/farmacologia , Doenças das Plantas/prevenção & controle , Arabidopsis/efeitos dos fármacos , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/microbiologia , Bioensaio , Botrytis/efeitos dos fármacos , Botrytis/fisiologia , Doenças das Plantas/microbiologia , Pseudomonas/efeitos dos fármacos , Pseudomonas/fisiologia
8.
PLoS Comput Biol ; 16(5): e1007934, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32453781

RESUMO

The effect of environmental fluctuations is a major question in ecology. While it is widely accepted that fluctuations and other types of disturbances can increase biodiversity, there are fewer examples of other types of outcomes in a fluctuating environment. Here we explore this question with laboratory microcosms, using cocultures of two bacterial species, P. putida and P. veronii. At low dilution rates we observe competitive exclusion of P. veronii, whereas at high dilution rates we observe competitive exclusion of P. putida. When the dilution rate alternates between high and low, we do not observe coexistence between the species, but rather alternative stable states, in which only one species survives and initial species' fractions determine the identity of the surviving species. The Lotka-Volterra model with a fluctuating mortality rate predicts that this outcome is independent of the timing of the fluctuations, and that the time-averaged mortality would also lead to alternative stable states, a prediction that we confirm experimentally. Other pairs of species can coexist in a fluctuating environment, and again consistent with the model we observe coexistence in the time-averaged dilution rate. We find a similar time-averaging result holds in a three-species community, highlighting that simple linear models can in some cases provide powerful insight into how communities will respond to environmental fluctuations.


Assuntos
Ecossistema , Enterobacter aerogenes/fisiologia , Microbiota , Pseudomonas putida/fisiologia , Pseudomonas/fisiologia , Teorema de Bayes , Biodiversidade , Técnicas de Cocultura , Simulação por Computador , Modelos Lineares , Modelos Biológicos , Microbiologia do Solo , Especificidade da Espécie
9.
PLoS One ; 15(4): e0231496, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32298309

RESUMO

In agroecosystems, soil biodiversity is increasingly becoming more recognized as providing benefits to both plants and human health. It performs a wide variety of ecological services beyond the recycling of nutrients to plant growth and manage pests and diseases below the economic injury level. This study investigated the effects of three Pseudomonas isolates (Q172B, Q110B and Q036B), isolated from untreated tomato rhizospheric soil, as a biological control agent of Bemisia tabaci which is a key pest of tomato crops. The study was conducted under laboratory and glasshouse conditions and the water treatment was used as a control. Adult mortality rates were assessed during three days at 24h interval and larva mortality rates were evaluated during six days after treatment at 48h interval. Results indicate that Q036B isolate has a faster effect on B. tabaci adult and larvae. Under laboratory conditions, all three Pseudomonas isolates (Q110B, Q036B and Q172B) have a significant effect on B. tabaci adult mortality compared to control. The earliest and the most important mortality rate of 76% was recorded by Q036B. Two isolates Q036B and Q110B caused a significant mortality on B. tabaci larvae; with highest mortality effect (79%) was observed for Q036B compared to control. However, Q172B has no mortality effects on B. tabaci larvae under laboratory conditions. In glasshouse conditions, only Q036B provided high mortality rates of 91% at 168h after treatment. The results of this study indicate that the Pseudomonas isolate Q036B significantly suppresses B. tabaci in tomato plant and could substitute the excessive use of chemicals. Current research indicates that soil biodiversity could be promising to preserve agro-ecological sustainability.


Assuntos
Produtos Agrícolas/microbiologia , Hemípteros , Lycopersicon esculentum/microbiologia , Controle Biológico de Vetores/métodos , Pseudomonas/fisiologia , Animais , Produtos Agrícolas/parasitologia , Larva , Lycopersicon esculentum/parasitologia , Microbiologia do Solo
10.
Appl Environ Microbiol ; 86(11)2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32245760

RESUMO

Obligate aerobic organisms rely on a functional electron transport chain for energy conservation and NADH oxidation. Because of this essential requirement, the genes of this pathway are likely constitutively and highly expressed to avoid a cofactor imbalance and energy shortage under fluctuating environmental conditions. We here investigated the essentiality of the three NADH dehydrogenases of the respiratory chain of the obligate aerobe Pseudomonas taiwanensis VLB120 and the impact of the knockouts of corresponding genes on its physiology and metabolism. While a mutant lacking all three NADH dehydrogenases seemed to be nonviable, the single or double knockout mutant strains displayed no, or only a weak, phenotype. Only the mutant deficient in both type 2 dehydrogenases showed a clear phenotype with biphasic growth behavior and a strongly reduced growth rate in the second phase. In-depth analyses of the metabolism of the generated mutants, including quantitative physiological experiments, transcript analysis, proteomics, and enzyme activity assays revealed distinct responses to type 2 and type 1 dehydrogenase deletions. An overall high metabolic flexibility enables P. taiwanensis to cope with the introduced genetic perturbations and maintain stable phenotypes, likely by rerouting of metabolic fluxes. This metabolic adaptability has implications for biotechnological applications. While the phenotypic robustness is favorable in large-scale applications with inhomogeneous conditions, the possible versatile redirecting of carbon fluxes upon genetic interventions can thwart metabolic engineering efforts.IMPORTANCE While Pseudomonas has the capability for high metabolic activity and the provision of reduced redox cofactors important for biocatalytic applications, exploitation of this characteristic might be hindered by high, constitutive activity of and, consequently, competition with the NADH dehydrogenases of the respiratory chain. The in-depth analysis of NADH dehydrogenase mutants of Pseudomonas taiwanensis VLB120 presented here provides insight into the phenotypic and metabolic response of this strain to these redox metabolism perturbations. This high degree of metabolic flexibility needs to be taken into account for rational engineering of this promising biotechnological workhorse toward a host with a controlled and efficient supply of redox cofactors for product synthesis.


Assuntos
Proteínas de Bactérias/genética , Mutação , NADH Desidrogenase/genética , Pseudomonas/fisiologia , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , NADH Desidrogenase/metabolismo , Oxirredução , Pseudomonas/genética , Análise de Sistemas
11.
Appl Environ Microbiol ; 86(12)2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32276979

RESUMO

It is important for the poultry industry to maximize product safety and quality by understanding the connection between bacterial diversity on chicken carcasses throughout poultry processing to the end of shelf life and the impact of the local processing environment. Enumeration of total aerobic bacteria, Campylobacter and Pseudomonas, and 16S rRNA gene amplicon sequencing were used to evaluate the processing line by collecting 10 carcasses from five processing steps: prescald, postplucker, pre- and post-immersion chill, and post-air chill. The diversity throughout a 12-day shelf life was also determined by examining 30 packaged carcasses. To identify the sources of possible contamination, scald water tank, immersion chilling water tank, air samples, and wall surfaces in the air-chill room were analyzed. Despite bacterial reductions on carcasses (>5 log10 CFU/ml) throughout the process, each step altered the bacterial diversity. Campylobacter was a minor but persistent component in the bacterial community on carcasses. The combination of scalding, defeathering, and plucking distributed thermophilic spore-forming Anoxybacillus to carcasses, which remained at a high abundance on carcasses throughout subsequent processes. Pseudomonas was not isolated from carcasses after air chilling but was abundant on the wall of the air-chill room and became the predominant taxon at the end of shelf life, suggesting possible contamination through air movement. The results suggest that attention is needed at each processing step, regardless of bacterial reductions on carcasses. Changing scalding water regularly, maintaining good hygiene practices during processing, and thorough disinfection at the end of each processing day are important to minimize bacterial transmission.IMPORTANCE Culture-based and culture-independent approaches were utilized to reveal bacterial community changes on chicken carcasses at different processing steps and potential routes from the local processing environment. Current commercial processing effectively reduced bacterial loads on carcasses. Poultry processes have similar processes across facilities, but various processing arrangements and operating parameters could impact the bacterial transmission and persistence on carcasses differently. This study showed the use of a single tunnel incorporating scalding, defeathering and plucking may undesirably distribute the thermoduric bacteria, e.g., Campylobacter and Anoxybacillus, between the local environment and carcasses, whereas this does not occur when these steps are separated. The length of immersion and air chilling also impacted bacterial diversity on carcasses. Air chilling can transfer Pseudomonas from wall surfaces onto carcasses; this may subsequently influence chicken product shelf life. This study helps poultry processors understand the impact of current commercial processing and improve the chicken product quality and safety.


Assuntos
Bactérias Aeróbias/fisiologia , Campylobacter/fisiologia , Manipulação de Alimentos , Microbiologia de Alimentos , Produtos Avícolas/microbiologia , Pseudomonas/fisiologia , Animais , Galinhas
12.
Nat Commun ; 11(1): 1741, 2020 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-32269224

RESUMO

Parental exposure to pathogens can prime offspring immunity in diverse organisms. The mechanisms by which this heritable priming occurs are largely unknown. Here we report that the soil bacteria Pseudomonas vranovensis is a natural pathogen of the nematode Caenorhabditis elegans and that parental exposure of animals to P. vranovensis promotes offspring resistance to infection. Furthermore, we demonstrate a multigenerational enhancement of progeny survival when three consecutive generations of animals are exposed to P. vranovensis. By investigating the mechanisms by which animals heritably adapt to P. vranovensis infection, we found that parental infection by P. vranovensis results in increased expression of the cysteine synthases cysl-1 and cysl-2 and the regulator of hypoxia inducible factor rhy-1 in progeny, and that these three genes are required for adaptation to P. vranovensis. These observations establish a CYSL-1, CYSL-2, and RHY-1 dependent mechanism by which animals heritably adapt to infection.


Assuntos
Adaptação Fisiológica , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/enzimologia , Caenorhabditis elegans/microbiologia , Cisteína Sintase/metabolismo , Padrões de Herança/genética , Pseudomonas/fisiologia , Adaptação Fisiológica/genética , Animais , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Cisteína Sintase/genética , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Modelos Biológicos
13.
J Appl Microbiol ; 129(3): 575-589, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32147927

RESUMO

OBJECTIVE: The present study was performed to examine the role of pqqE inhabiting rhizobacteria in organic acid production and relationship of the organic acids with phosphate solubilization by the bacteria in vitro as well as in vivo. METHODS AND RESULTS: The pqqE gene was PCR amplified and sequenced in genomic DNA of Pantoea sp. WP-5 and Pseudomonas sp. NN-4. Nucleotide sequence obtained from WP-5 and NN-4 showed maximum sequence similarity (88 and 89%, respectively) with the pqqE gene of Pseudomonas fluorescens strain CMR12a (KM251420). Deduced amino acid sequence from pqqE gene of Pseudomonas sp. NN-4 and Pantoea sp. WP-5 showed 75 and 93% similarity, respectively, with protein pyrroloquinoline quinone. Phosphate solubilization and acid production assay were quantified on spectrophotometer and high-profile liquid chromatograph, respectively, by each bacterial strain. Both strains produced organic acids such as acetic, citric, gluconic, succinic and malic acid and lowered the pH of Pikovskaya broth medium under laboratory conditions. Phosphate solubilization by Pantoea sp. WP-5 was 311 ± 4 and 204 ± 3 µg ml-1 in the culture medium supplemented with glucose and sucrose as carbon source, respectively. Pseudomonas sp. NN-4 solubilized 176 ± 3 and 298 ± 5 µg ml-1 phosphate in Pikovskaya broth medium under similar conditions. In field experiments conducted during two consecutive years, the concentration of acetic acid and gluconic acid was higher in root exudates of plants treated with Pantoea sp. WP-5 at 30% reduced doses of nitrogen (N)- and phosphorus (P)-based chemical fertilizers as compared to non-inoculated plants. Values of chlorophyll contents, crop growth rate, leaf area index, straw yield and P contents were recorded higher in plants inoculated with Pantoea sp. WP-5 and Pseudomonas sp. NN-4 as compared to non-inoculated control. Grain yield was increased by 10-12% due to inoculation with Pantoea sp. WP-5 and Pseudomonas sp. NN-4 over non-inoculated control in the field experiments. CONCLUSIONS: These results lead to the conclusions that the rhizobacteria inhabiting pqqE gene produced organic acids and solubilized the phosphate in vitro. On inoculation to wheat plants in field experiments, these strains produced the organic acids, solubilized the phosphate, and improved the P uptake and productivity of wheat. SIGNIFICANCE AND IMPACT OF THE STUDY: The Pantoea sp. WP-5 and Pseudomonas sp. NN-4 are the potential candidates for inoculation to wheat as phosphate solubilizer even with reduced chemical fertilizer dose. The inoculation of the strains may enhance grain yield and net income of the farmer even with less chemical fertilizer application. This practice will be helpfull inminimizing environmental pollution.


Assuntos
Proteínas de Bactérias/genética , Pantoea/fisiologia , Pseudomonas/fisiologia , Triticum/crescimento & desenvolvimento , Triticum/microbiologia , Ácidos/metabolismo , Proteínas de Bactérias/metabolismo , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Fertilizantes/análise , Pantoea/genética , Pantoea/metabolismo , Fosfatos/metabolismo , Pseudomonas/genética , Pseudomonas/metabolismo , Solo/química , Microbiologia do Solo , Triticum/metabolismo
14.
Electron. j. biotechnol ; 44: 14-18, Mar. 2020. ilus, graf
Artigo em Inglês | LILACS | ID: biblio-1087629

RESUMO

BACKGROUND: Although bioactive metabolites capable of causing oxidative photo-necrosis in plant tissues have been identified in fungi, little is known about this type of mechanism in bacteria. These metabolites act as photosensitizers that generate reactive oxygen species (ROS) capable of causing damage to cells. In addition, these metabolites can pass into an energetically excited state when they receive some luminous stimulus, a condition in which they interact with other molecules present in the environment, such as molecular oxygen (O2), also known as triplet oxygen (3 O2), generating ROS. RESULTS: The suspension of the bacterial culture of Pseudomonas cedrina was shown to produce foliar necrosis in papaya leaves (Carica papaya L.) only in the presence of sunlight, which is evidence of photosensitizing mechanisms that generate singlet oxygen (1 O2). From the chemical study of extracts obtained from this bacteria, 3-(4-(2-carboxipropyl) phenyl) but-2-enoic acid (1) was isolated. This compound, in the presence of light and triplet oxygen (3 O2), was able to oxidize ergosterol to its peroxide, since it acted as a photosensitizer producing 1 O2, with which it was corroborated that a photosensitization reaction occurs, mechanism by which this bacterium could prove to cause oxidative foliar photo-necrosis. CONCLUSIONS: P. cedrina was able to induce oxidative foliar photo-necrosis because of its potential ability to produce photosensitizing metabolites that generate singlet oxygen in the plants it colonizes. Based on the above, it can be proposed that some bacteria can cause oxidative foliar photo-necrosis as an important mechanism in the pathogenesis of host species.


Assuntos
Doenças das Plantas/microbiologia , Pseudomonas/fisiologia , Carica/microbiologia , Oxigênio Singlete/metabolismo , Pseudomonas/metabolismo , Ácidos , Espécies Reativas de Oxigênio , Folhas de Planta/microbiologia , Foto-Oxidação , Luz , Necrose
16.
Can J Microbiol ; 66(5): 368-376, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32040347

RESUMO

Conventional weed control methods often have environmental impact. The present study was conducted to screen selected accessions of Pseudomonas for both potential biocontrol of Phalaris minor and Avena fatua and potential concurrent growth promotion of wheat. The four Pseudomonas strains (B11, T19, T24, and T75) were found positive for cyanide production, siderophore production, phosphorus solubilization, oxidase activity, catalase activity, and ACC deaminase activity in vitro. These strains were phytotoxic, causing up to 73.3% mortality in the lettuce seedling bioassay. Consortia of compatible Pseudomonas strains increased A. fatua and P. minor seedling mortality up to 50.0% and 56.7%, respectively, and reduced root length up to 73.8% and 53.9%, respectively, as compared with the uninoculated control. Consortia of compatible Pseudomonas strains increased wheat shoot length, root length, fresh biomass, dry biomass, and leaf greenness up to 41.6%, 100%, 79.9%, 81.5%, and 21.1%, respectively, over the uninoculated control. Four of the 11 Pseudomonas consortia tested expressed good weed suppression and wheat growth promotion capacity and deserve further experimentation. The findings from this study may lead to the formulation of bioherbicides that will improve human and environmental health.


Assuntos
Avena/microbiologia , Phalaris/microbiologia , Pseudomonas/fisiologia , Triticum/crescimento & desenvolvimento , Controle de Plantas Daninhas/métodos , Humanos , Plântula/microbiologia , Sementes/microbiologia
17.
J Appl Microbiol ; 128(6): 1720-1734, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31957222

RESUMO

AIMS: This study investigated the adaptation strategies of Pseudomonas protegens to hyperosmotic growth environments (HGE). METHODS AND RESULTS: The current study combined transcriptomics and proteomics to provide an overview of the molecular mechanism of P. protegens adaptation to HGE. The results revealed that HGE exerted prominent impact on the synthesis of proteins involved in multiple cellular functions. Comparison of the differentially accumulated proteins at both transcriptomics and proteomics levels indicated the existence of complex post-transcriptional modification during P. protegens hyperosmotic adaptation. CONCLUSIONS: During HGE adaptation, the cells form a complex self-protection mechanism. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of the current study can help researchers to gain insights regarding the mechanism of P. protegens adaptation to HGE. These findings provide information for the application of stress methods and facilitate its broad commercial utilization.


Assuntos
Aclimatação , Pressão Osmótica , Pseudomonas/fisiologia , Aclimatação/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Proteômica , Pseudomonas/genética , Pseudomonas/metabolismo
18.
J Med Microbiol ; 69(3): 347-360, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31976855

RESUMO

Pseudomonas brassicacearum is one of over fifty species of bacteria classified into the P. fluorescens group. Generally considered a harmless commensal, these bacteria are studied for their plant-growth promotion (PGP) and biocontrol characteristics. Intriguingly, P. brassicacearum is closely related to P. corrugata, which is classified as an opportunistic phytopathogen. Twenty-one P. brassicacearum genomes have been sequenced to date. In the current review, genomes of P. brassicacearum and strains from the P. corrugata clade were mined for regions associated with PGP, biocontrol and pathogenicity. We discovered that 'beneficial' bacteria and those classified as plant pathogens have many genes in common; thus, only a fine line separates beneficial/harmless commensals from those capable of causing disease in plants. The genotype and physiological state of the plant, the presence of biotic/abiotic stressors, and the ability of bacteria to manipulate the plant immune system collectively contribute to how the bacterial-plant interaction plays out. Because production of extracellular metabolites is energetically costly, these compounds are expected to impart a fitness advantage to the producer. P. brassicacearum is able to reduce the threat of nematode predation through release of metabolites involved in biocontrol. Moreover this bacterium has the unique ability to form biofilms on the head of Caenorhabditis elegans, as a second mechanism of predator avoidance. Rhizobacteria, plants, fungi, and microfaunal predators have occupied a shared niche for millions of years and, in many ways, they function as a single organism. Accordingly, it is essential that we appreciate the dynamic interplay among these members of the community.


Assuntos
Biofilmes/crescimento & desenvolvimento , Caenorhabditis elegans/microbiologia , Genoma Bacteriano/genética , Doenças das Plantas/microbiologia , Plantas/microbiologia , Pseudomonas/fisiologia , Animais , Lipopeptídeos/genética , Controle Biológico de Vetores , Pseudomonas/genética , Pseudomonas/crescimento & desenvolvimento , Transdução de Sinais , Simbiose
19.
BMC Evol Biol ; 20(1): 13, 2020 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-31992187

RESUMO

BACKGROUND: The theory of trade-off suggests that limited resources should lead to trade-off in resource intensive traits such as, immunity related and sexually selected traits in males. Alternatively, sexual exaggerations can also act as an honest indicator of underlying immunocompetence, leading to positive correlations between these traits. Evidences in support of either hypothesis in invertebrates are equivocal. Whereas several studies have addressed this question, few have used naturally occurring pathogens and realized post infection realized immunity (e.g., survivorship) to assay the fitness correlations between these two sets of traits. RESULTS: Adopting an experimental evolution approach, we evolved replicate populations of Drosophila melanogaster under high and low sexual selection regimes for over a hundred generations and found the following in virgin and mated males in three separate assays: a.Post infection survivorship against two natural pathogens - Pseudomonas entomophila (Pe) and Staphylococcus succinus (Ss): Mated males survived better against Pe, but were no different than virgins against Ss.b.Bacterial clearance ability against a third natural pathogen Providencia rettgeri (Pr): Mated males had significantly lower CFUs than virgins. However, sexual selection history had no effect on realized immunity of either virgin or mated males. CONCLUSION: We show that while mating can affect realized immunity in a pathogen specific way, sexual selection did not affect the same. The results highlight that complex polygenic traits such as immunity and reproductive traits not necessarily evolve following a binary trade-off model. We also stress the importance natural pathogens while studying sexual selection-immunity correlations.


Assuntos
Evolução Biológica , Drosophila melanogaster/imunologia , Drosophila melanogaster/fisiologia , Imunidade , Seleção Genética , Comportamento Sexual Animal/fisiologia , Animais , Contagem de Colônia Microbiana , Drosophila melanogaster/microbiologia , Feminino , Masculino , Fenótipo , Modelos de Riscos Proporcionais , Pseudomonas/fisiologia , Reprodução/fisiologia , Staphylococcus/fisiologia
20.
Evolution ; 74(2): 338-348, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31814118

RESUMO

Mechanisms of resistance to pathogens and parasites are thought to be costly and thus to lead to evolutionary trade-offs between resistance and life-history traits expressed in the absence of the infective agents. On the other hand, sexually selected traits are often proposed to indicate "good genes" for resistance, which implies a positive genetic correlation between resistance and success in sexual selection. Here I show that experimental evolution of improved resistance to the intestinal pathogen Pseudomonas entomophila in Drosophila melanogaster was associated with a reduction in male sexual success. Males from four resistant populations achieved lower paternity than males from four susceptible control populations in competition with males from a competitor strain, indicating an evolutionary cost of resistance in terms of mating success and/or sperm competition. In contrast, no costs were found in larval viability, larval competitive ability and population productivity assayed under nutritional limitation; together with earlier studies this suggests that the costs of P. entomophila resistance for nonsexual fitness components are negligible. Thus, rather than indicating heritable pathogen resistance, sexually selected traits expressed in the absence of pathogens may be sensitive to costs of resistance, even if no such costs are detected in other fitness traits.


Assuntos
Drosophila melanogaster/fisiologia , Interações Hospedeiro-Patógeno/fisiologia , Pseudomonas/fisiologia , Seleção Genética , Comportamento Sexual Animal , Animais , Evolução Biológica , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/microbiologia , Feminino , Larva/crescimento & desenvolvimento , Larva/microbiologia , Larva/fisiologia , Longevidade , Masculino
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