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Applied Microbiology and Biotechnology Dec 2020Pseudomonas chlororaphis is a plant-associated bacterium with reported antagonistic activity against different organisms and plant growth-promoting properties. P....
Pseudomonas chlororaphis is a plant-associated bacterium with reported antagonistic activity against different organisms and plant growth-promoting properties. P. chlororaphis possesses exciting biotechnological features shared with another Pseudomonas with a nonpathogenic phenotype. Part of the antagonistic role of P. chlororaphis is due to its production of a wide variety of phenazines. To expand the knowledge of the metabolic traits of this organism, we constructed the first experimentally validated genome-scale model of P. chlororaphis ATCC 9446, containing 1267 genes and 2289 reactions, and analyzed strategies to maximize its potential for the production of phenazine-1-carboxamide (PCN). The resulting model also describes the capability of P. chlororaphis to carry out the denitrification process and its ability to consume sucrose (Scr), trehalose, mannose, and galactose as carbon sources. Additionally, metabolic network analysis suggested fatty acids as the best carbon source for PCN production. Moreover, the optimization of PCN production was performed with glucose and glycerol. The optimal PCN production phenotype requires an increased carbon flux in TCA and glutamine synthesis. Our simulations highlight the intrinsic HO flux associated with PCN production, which may generate cellular stress in an overproducing strain. These results suggest that an improved antioxidative strategy could lead to optimal performance of phenazine-producing strains of P. chlororaphis. KEY POINTS : • This is the first publication of a metabolic model for a strain of P. chlororaphis. • Genome-scale model is worthy tool to increase the knowledge of a non model organism. • Fluxes simulations indicate a possible effect of HO on phenazines production. • P. chlororaphis can be a suitable model for a wide variety of compounds.
Topics: Hydrogen Peroxide; Phenazines; Pseudomonas; Pseudomonas chlororaphis
PubMed: 32984920
DOI: 10.1007/s00253-020-10913-4 -
Biology Sep 2023Phenazine compounds are widely used in agricultural control and the medicine industry due to their high inhibitory activity against pathogens and antitumor activity. The...
Phenazine compounds are widely used in agricultural control and the medicine industry due to their high inhibitory activity against pathogens and antitumor activity. The green and sustainable method of synthesizing phenazine compounds through microbial fermentation often requires a complex culture medium containing tryptone and yeast extract, and its cost is relatively high, which greatly limits the large-scale industrial production of phenazine compounds by fermentation. The aim of this study was to develop a cost-effective minimal medium for the efficient synthesis of phenazine compounds by . Through testing the minimum medium commonly used by , an ME medium for with a high production of phenazine compounds was obtained. Then, the components of the ME medium and the other medium were compared and replaced to verify the beneficial promoting effect of Fe and NH on phenazine compounds. A cost-effective general defined medium (GDM) using glycerol as the sole carbon source was obtained by optimizing the composition of the ME medium. Using the GDM, the production of phenazine compounds by reached 1073.5 mg/L, which was 1.3 times that achieved using a complex medium, while the cost of the GDM was only 10% that of a complex medium (e.g., the KB medium). Finally, by engineering the glycerol metabolic pathway, the titer of phenazine-1-carboxylic acid reached the highest level achieved using a minimum medium so far. This work demonstrates how we systematically analyzed and optimized the composition of the medium and integrated a metabolic engineering method to obtain the most cost-effective fermentation strategy.
PubMed: 37887002
DOI: 10.3390/biology12101292 -
Microbiological Research Aug 2020Pseudomonas chlororaphis subsp. aurantiaca strain JD37 is a plant growth-promoting rhizobacterium (PGPR), which has important biotechnological features such as plant...
Genome analysis of plant growth-promoting rhizobacterium Pseudomonas chlororaphis subsp. aurantiaca JD37 and insights from comparasion of genomics with three Pseudomonas strains.
Pseudomonas chlororaphis subsp. aurantiaca strain JD37 is a plant growth-promoting rhizobacterium (PGPR), which has important biotechnological features such as plant growth promotion, rhizosphere colonization and biocontrol activities. In present study, the genome sequence of JD37 was obtained and comparative genomic analysis were performed to explore unique features of the JD37 genome and its relationship with other Pseudomonas PGPR: P. chlororaphis PA23, P. protegens Pf-5 and P. aeruginosa M18. JD37 possessed a single circular chromosome of 6,702,062 bp in length with an average GC content of 62.75 %. No plasmid was detected in JD37. A total of 5003 functional proteins of JD37 were predicted according to the clusters of orthologous groups (COGs) database. The JD37 genome consisted of various genes involved in plant growth promotion, biocontrol activities and defense responses. Genes involved in the rhizosphere colonization and motility were also found in the genome of JD37, suggesting the common plant growth-promoting traits in PGPR. The identified resistance genes (e.g. those related to metal resistance, antibiotics, and osmotic and temperature-shock) and secondary metabolite biosynthesis revealed the pathways for metabolites it produced. Data presented in present study further provided valuable information on its molecular genetics and adaptive capacity in the rhizosphere niche.
Topics: Disease Resistance; Drug Resistance, Microbial; Gene Ontology; Genes, Bacterial; Genome, Bacterial; Genomics; Phylogeny; Plant Development; Pseudomonas; Rhizosphere; Secondary Metabolism
PubMed: 32402945
DOI: 10.1016/j.micres.2020.126483 -
Microorganisms Jan 2021To guarantee the supply of critical elements in the future, the development of new technologies is essential. Siderophores have high potential in the recovery and...
To guarantee the supply of critical elements in the future, the development of new technologies is essential. Siderophores have high potential in the recovery and recycling of valuable metals due to their metal-chelating properties. Using the Chrome azurol S assay, 75 bacterial strains were screened to obtain a high-yield siderophore with the ability to complex valuable critical metal ions. The siderophore production of the four selected strains 3E, DSM 50083, EPS, and B7g was optimized, resulting in significantly increased siderophore production of and . Produced siderophore amounts and velocities were highly dependent on the carbon source. The genomes of and were sequenced. Bioinformatical analyses revealed the occurrence of an achromobactin and a pyoverdine gene cluster in , a heterobactin and a requichelin gene cluster in , and a desferrioxamine gene cluster in Finally, the results of the previous metal-binding screening were validated by a proof-of-concept development for the recovery of metal ions from aqueous solutions utilizing C columns functionalized with siderophores. We demonstrated the recovery of the critical metal ions V(III), Ga(III), and In(III) from mixed metal solutions with immobilized siderophores of and
PubMed: 33466508
DOI: 10.3390/microorganisms9010111 -
Environmental Science & Technology Oct 2021Strategies to reduce crop losses due to drought are needed as climate variability affects agricultural productivity. Wheat ( var. Juniper) growth in a...
Strategies to reduce crop losses due to drought are needed as climate variability affects agricultural productivity. Wheat ( var. Juniper) growth in a nutrient-sufficient, solid growth matrix containing varied doses of CuO, ZnO, and SiO nanoparticles (NPs) was used to evaluate NP mitigation of drought stress. NP amendments were at fertilizer levels, with maxima of 30 Cu, 20 Zn, and 200 Si (mg metal/kg matrix). Seeds of this drought-tolerant cultivar were inoculated with O6 (O6) to provide a protective root microbiome. An 8 day drought imposed on 14 day-old wheat seedlings decreased shoot and root mass, shoot water content, and the quantum yield of photosystem II when compared to watered plants. O6 root colonization was not impaired by drought or NPs. A dose-dependent increase in the Cu, Zn, and Si from the NPs was observed from analysis of the rhizosphere solution, and this process was not affected by drought. Consequently, fertilizer concentrations of the NPs did not further improve drought tolerance in wheat seedlings under the growth conditions of adequate mineral nutrition and the presence of a beneficial microbiome. These findings suggest that potential NP benefits in promoting plant drought tolerance occur only under certain environmental conditions.
Topics: Droughts; Nanoparticles; Nutrients; Plant Roots; Seedlings; Silicon Dioxide; Triticum; Zinc Oxide
PubMed: 34009961
DOI: 10.1021/acs.est.1c00453 -
Frontiers in Microbiology 2023The spectral distribution of light (different wavelength) has recently been identified as an important factor in the dynamics and function of leaf-associated microbes....
BACKGROUND
The spectral distribution of light (different wavelength) has recently been identified as an important factor in the dynamics and function of leaf-associated microbes. This study investigated the impact of different wavelength on three commercial biocontrol agents (BCA): (BA), (PC), and (SG).
METHODS
The impact of light exposure on sole carbon source utilization, biofilm formation, and biosurfactant production by the selected BCA was studied using phenotypic microarray (PM) including 190 sole carbon sources (OmniLog®, PM panels 1 and 2). The BCA were exposed to five monochromatic light conditions (420, 460, 530, 630, and 660 nm) and darkness during incubation, at an intensity of 50 μmol m s.
RESULTS
Light exposure together with specific carbon source increased respiration in all three BCA. Different wavelengths of light influenced sole carbon utilization for the different BCA, with BA and PC showing increased respiration when exposed to wavelengths within the blue spectrum (420 and 460 nm) while respiration of selected carbon sources by SG increased in the presence of red light (630 and 660 nm). Only one carbon source (capric acid) generated biosurfactant production in all three BCA. A combination of specific wavelength of light and sole carbon source increased biofilm formation in all three BCA. BA showed significantly higher biofilm formation when exposed to blue (460 nm) and green (530 nm) light and propagated in D-sucrose, D-fructose, and dulcitol. PC showed higher biofilm formation when exposed to blue light. Biofilm formation by SG increased when exposed to red light (630 nm) and propagated in citraconic acid.
CONCLUSION
To increase attachment and success in BCA introduced into the phyllosphere, a suitable combination of light quality and nutrient conditions could be used.
PubMed: 36819051
DOI: 10.3389/fmicb.2023.1087639 -
Environmental Microbiology Apr 2021Pseudomonas chlororaphis PCL1606 (PcPCL1606) displays plant-colonizing features and exhibits antagonistic traits against soil-borne phytopathogenic fungi. Biofilm...
Pseudomonas chlororaphis PCL1606 (PcPCL1606) displays plant-colonizing features and exhibits antagonistic traits against soil-borne phytopathogenic fungi. Biofilm formation could be relevant for the PcPCL1606 lifestyle, and in this study the role of some putative extracellular matrix components (EMC; Fap-like fibre, alginate and Psl-like polysaccharides) in the biofilm architecture and biocontrol activity of this bacterium were determined. EMC such as the Fap-like fibre and alginate polysaccharide play secondary roles in biofilm formation in PcPCL1606, because they are not fundamental to its biofilm architecture in flow cell chamber, but synergistically they have shown to favour bacterial competition during biofilm formation. Conversely, studies on Psl-like polysaccharide have revealed that it may contain mannose, and that it is strongly involved in the PcPCL1606 biofilm architecture and niche competition. Furthermore, the Fap-like fibre and Psl-like exopolysaccharide play roles in early surface attachment and contribute to biocontrol activity against the white root rot disease caused by Rosellinia necatrix in avocado plants. These results constitute the first report regarding the study of the extracellular matrix of the PcPCL1606 strain and highlight the importance of a putative Fap-like fibre and Psl-like exopolysaccharide produced by PcPCL1606 in the biofilm formation process and interactions with the host plant root.
Topics: Ascomycota; Biofilms; Extracellular Matrix; Polysaccharides, Bacterial; Pseudomonas aeruginosa; Pseudomonas chlororaphis; Xylariales
PubMed: 33314481
DOI: 10.1111/1462-2920.15355 -
Applied and Environmental Microbiology Feb 2020Bacterial rhizosphere colonization is critical for phytobeneficial rhizobacteria such as phenazine-producing spp. To better understand this colonization process,...
Bacterial rhizosphere colonization is critical for phytobeneficial rhizobacteria such as phenazine-producing spp. To better understand this colonization process, potential metabolic and genomic determinants required for rhizosphere colonization were identified using a collection of 60 phenazine-producing strains isolated from multiple plant species and representative of the worldwide diversity. and (potato) were used as host plants. Bacterial rhizosphere colonization was measured by quantitative PCR using a newly designed primer pair and TaqMan probe targeting a conserved region of the phenazine biosynthetic operon. The metabolic abilities of the strains were assessed on 758 substrates using Biolog phenotype microarray technology. These data, along with available genomic sequences for all strains, were analyzed in light of rhizosphere colonization. Strains belonging to the subgroup colonized the rhizospheres of both plants more efficiently than strains belonging to the subgroup. Metabolic results indicated that the ability to use amines and amino acids was associated with an increase in rhizosphere colonization capability in and/or in The presence of multiple genetic determinants in the genomes of the different strains involved in catabolic pathways and plant-microbe and microbe-microbe interactions correlated with increased or decreased rhizosphere colonization capabilities in both plants. These results suggest that the metabolic and genomic traits found in different phenazine-producing strains reflect their rhizosphere competence in and Interestingly, most of these traits are associated with similar rhizosphere colonizing capabilities in both plant species. Rhizosphere colonization is crucial for plant growth promotion and biocontrol by antibiotic-producing spp. This colonization process relies on different bacterial determinants which partly remain to be uncovered. In this study, we combined a metabolic and a genomic approach to decipher new rhizosphere colonization determinants which could improve our understanding of this process in spp. Using 60 distinct strains of phenazine-producing spp., we show that rhizosphere colonization abilities correlated with both metabolic and genomic traits when these bacteria were inoculated on two distant plants, and Key metabolic and genomic determinants presumably required for efficient colonization of both plant species were identified. Upon further validation, these targets could lead to the development of simple screening tests to rapidly identify efficient rhizosphere colonizers.
Topics: Arabidopsis; Genome, Bacterial; Phenazines; Pseudomonas; Rhizosphere; Solanum tuberosum
PubMed: 31811040
DOI: 10.1128/AEM.02443-19 -
Journal of Agricultural and Food... Dec 2020Phenazine-1-carboxylic acid (PCA), the primary active ingredient of Shenqinmycin, was awarded the China Pesticide Certificate in 2011 due to its excellent antibacterial...
Phenazine-1-carboxylic acid (PCA), the primary active ingredient of Shenqinmycin, was awarded the China Pesticide Certificate in 2011 due to its excellent antibacterial action. Phenazine-1-carboxamide (PCN) is a derivative of PCA, which is modified by the gene, and its anti-bacterial effect is better than that of PCA. At present, PCN can be produced via fermentation using an opportunistic pathogen, . Qlu-1 is an environmentally friendly strain of that can produce phenazine derivatives. We replaced the gene with the gene from to achieve PCN accumulation. Different strategies were used to enhance PCN production: knocking out of negative regulatory factors, enhancing the shikimate pathway by gene overexpression and gene knocking, and using fed-batch fermentation. Finally, an engineered strain of was produced, which produced 11.45 g/L PCN. This achievement indicates that Qlu-1 could be modified as a potential microbial cell factory for PCN production by metabolic engineering.
Topics: Bacterial Proteins; Metabolic Engineering; Multigene Family; Phenazines; Pseudomonas aeruginosa; Pseudomonas chlororaphis
PubMed: 33287542
DOI: 10.1021/acs.jafc.0c05746 -
Applied Microbiology and Biotechnology Oct 2021Phenazine-1-carboxylic acid and pyrrolnitrin, the two secondary metabolites produced by Pseudomonas chlororaphis G05, serve as biocontrol agents that mainly contribute...
Phenazine-1-carboxylic acid and pyrrolnitrin, the two secondary metabolites produced by Pseudomonas chlororaphis G05, serve as biocontrol agents that mainly contribute to the growth repression of several fungal phytopathogens. Although some regulators of phenazine-1-carboxylic acid biosynthesis have been identified, the regulatory pathway involving phenazine-1-carboxylic acid synthesis is not fully understood. We isolated a white conjugant G05W03 on X-Gal-containing LB agar during our screening of novel regulator candidates using transposon mutagenesis with a fusion mutant G05Δphz::lacZ as a recipient. By cloning of DNA adjacent to the site of the transposon insertion, we revealed that a LysR-type transcriptional regulator (LTTR) gene, finR, was disrupted in the conjugant G05W03. To confirm the regulatory function of FinR, we constructed the finR-knockout mutant G05ΔfinR, G05Δphz::lacZΔfinR, and G05Δprn::lacZΔfinR, using the wild-type strain G05 and its fusion mutant derivatives as recipient strains, respectively. We found that the expressions of phz and prn operons were dramatically reduced in the finR-deleted mutant. With quantification of the production of antifungal metabolites biosynthesized by the finR-negative strain G05ΔfinR, it was shown that FinR deficiency also led to decreased yield of phenazine-1-carboxylic acid and pyrrolnitrin. In addition, the pathogen inhibition assay confirmed that the production of phenazine-1-carboxylic acid was severely reduced in the absence of FinR. Transcriptional fusions and qRT-PCR verified that FinR could positively govern the transcription of the phz and prn operons. Taken together, FinR is required for antifungal metabolite biosynthesis and crop protection against some fungal pathogens.Key points• A novel regulator FinR was identified by transposon mutagenesis.• FinR regulates antifungal metabolite production.• FinR regulates the phz and prn expression by binding to their promoter regions.
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Operon; Phenazines; Pseudomonas chlororaphis; Pyrrolnitrin
PubMed: 34562115
DOI: 10.1007/s00253-021-11600-8