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Genomics Data Jun 2015Pseudomonas chlororaphis HT66, a plant growth-promoting rhizobacterium that produces phenazine-1-carboxamide with high yield, was compared with three genomic sequenced...
Pseudomonas chlororaphis HT66, a plant growth-promoting rhizobacterium that produces phenazine-1-carboxamide with high yield, was compared with three genomic sequenced P. chlororaphis strains, GP72, 30-84 and O6. The genome sizes of four strains vary from 6.66 to 7.30 Mb. Comparisons of predicted coding sequences indicated 4833 conserved genes in 5869-6455 protein-encoding genes. Phylogenetic analysis showed that the four strains are closely related to each other. Its competitive colonization indicates that P. chlororaphis can adapt well to its environment. No virulence or virulence-related factor was found in P. chlororaphis. All of the four strains could synthesize antimicrobial metabolites including different phenazines and insecticidal protein FitD. Some genes related to the regulation of phenazine biosynthesis were detected among the four strains. It was shown that P. chlororaphis is a safe PGPR in agricultural application and could also be used to produce some phenazine antibiotics with high-yield.
PubMed: 26484173
DOI: 10.1016/j.gdata.2015.01.006 -
PloS One 2015Pseudomonas chlororaphis strain PA23 is a biocontrol agent able to suppress growth of the fungal pathogen Sclerotinia sclerotiorum. This bacterium produces an arsenal of...
Pseudomonas chlororaphis strain PA23 is a biocontrol agent able to suppress growth of the fungal pathogen Sclerotinia sclerotiorum. This bacterium produces an arsenal of exometabolites including pyrrolnitrin (PRN), phenazine (PHZ), hydrogen cyanide (HCN), and degradative enzymes. Production of these compounds is controlled at both the transcriptional and posttranscriptional levels by the Gac-Rsm system, RpoS, PsrA, and the Phz quorum-sensing system. Beyond pathogen-suppression, the success of a biocontrol agent is dependent upon its ability to establish itself in the environment where predation by bacterivorous organisms, including nematodes, may threaten persistence. The focus of this study was to investigate whether PA23 is able to resist grazing by Caenorhabditis elegans and to define the role played by exoproducts in the bacterial-nematode interaction. We discovered that both PRN and HCN contribute to fast- and slow-killing of C. elegans. HCN is well-established as having lethal effects on C. elegans; however, PRN has not been reported to be nematicidal. Exposure of L4 stage nematodes to purified PRN reduced nematode viability in a dose-dependent fashion and led to reduced hatching of eggs laid by gravid adults. Because bacterial metabolites can act as chemoattractants or repellents, we analyzed whether PA23 exhibited attractant or repulsive properties towards C. elegans. Both PRN and HCN were found to be potent repellents. Next we investigated whether the presence of C. elegans would elicit changes in PA23 gene activity. Co-culturing the two organisms increased expression of a number of genes associated with biocontrol, including phzA, hcnA, phzR, phzI, rpoS and gacS. Exoproduct analysis showed that PHZ and autoinducer signals were upregulated, consistent with the gene expression profiles. Collectively, these findings indicate that PA23 is able to sense the presence of C. elegans and it is able to both repel and kill the nematodes, which should facilitate environmental persistence and ultimately biocontrol.
Topics: Animals; Antinematodal Agents; Biological Assay; Caenorhabditis elegans; Gene Expression Regulation, Bacterial; Hydrogen Cyanide; Oviposition; Pest Control, Biological; Pseudomonas; Pyrrolnitrin
PubMed: 25901993
DOI: 10.1371/journal.pone.0123184 -
Molecular Plant-microbe Interactions :... Mar 2015Pseudomonas chlororaphis PCL1606 is a rhizobacterium that has biocontrol activity against many soilborne phytopathogenic fungi. The whole genome sequence of this strain... (Comparative Study)
Comparative Study
Pseudomonas chlororaphis PCL1606 is a rhizobacterium that has biocontrol activity against many soilborne phytopathogenic fungi. The whole genome sequence of this strain was obtained using the Illumina Hiseq 2000 sequencing platform and was assembled using SOAP denovo software. The resulting 6.66-Mb complete sequence of the PCL1606 genome was further analyzed. A comparative genomic analysis using 10 plant-associated strains within the fluorescent Pseudomonas group, including the complete genome of P. chlororaphis PCL1606, revealed a diverse spectrum of traits involved in multitrophic interactions with plants and microbes as well as biological control. Phylogenetic analysis of these strains using eight housekeeping genes clearly placed strain PCL1606 into the P. chlororaphis group. The genome sequence of P. chlororaphis PCL1606 revealed the presence of sequences that were homologous to biosynthetic genes for the antifungal compounds 2-hexyl, 5-propyl resorcinol (HPR), hydrogen cyanide, and pyrrolnitrin; this is the first report of pyrrolnitrin encoding genes in this P. chlororaphis strain. Single-, double-, and triple-insertional mutants in the biosynthetic genes of each antifungal compound were used to test their roles in the production of these antifungal compounds and in antagonism and biocontrol of two fungal pathogens. The results confirmed the function of HPR in the antagonistic phenotype and in the biocontrol activity of P. chlororaphis PCL1606.
Topics: Antifungal Agents; Base Sequence; Biological Control Agents; Comparative Genomic Hybridization; Fusarium; Genome, Bacterial; Genomics; Solanum lycopersicum; Molecular Sequence Data; Mutagenesis, Insertional; Persea; Phenotype; Phylogeny; Plant Diseases; Plant Roots; Pseudomonas; Pyrrolnitrin; Resorcinols; Sequence Analysis, DNA; Xylariales
PubMed: 25679537
DOI: 10.1094/MPMI-10-14-0326-FI -
3 Biotech Feb 2015A diverse and versatile spectrum of metabolic activities among isolates of fluorescent Pseudomonas putida indicates their adaptability to various niches. These...
Genotypic and phenotypic diversity of polyhydroxybutyrate (PHB) producing Pseudomonas putida isolates of Chhattisgarh region and assessment of its phosphate solubilizing ability.
A diverse and versatile spectrum of metabolic activities among isolates of fluorescent Pseudomonas putida indicates their adaptability to various niches. These polyhydroxybutyrate producing and phosphate solubilizing isolates showed a high level of functional and genetic versatility among themselves. One of the potential P. putida isolate P132 can contribute as a candidate agent for both biocontrol and PGPR applications. Identified as one of the most efficient PHB producer and phosphate solubilizer, in vitro detection of P132 showed the presence of genes for phenazine, pyrrolnitrin, pyoluteorin and 2,4 diacetylphloroglucinol along with polyhydroxyalkanoate.
PubMed: 28324359
DOI: 10.1007/s13205-014-0198-9 -
Microbial Biotechnology May 2015The aim of this study was to inventory the types of plant growth-promoting rhizobacteria (PGPR) present in the rhizosphere of plants grown in soils contaminated with...
The aim of this study was to inventory the types of plant growth-promoting rhizobacteria (PGPR) present in the rhizosphere of plants grown in soils contaminated with heavy metals, recalcitrant organics, petroleum sewage or salinity in China. We screened 1223 isolates for antifungal activity and about 24% inhibited Rhizoctonia solani or Sclerotinia sclerotiorum. Twenty-four strains inhibitory to R. solani, Gaeumannomyces graminis var. tritici and/or S. sclerotiorum and representing the dominant morphotypes were assayed for PGPR activity. Seven strains contained phlD, prnD, pltC or phzF genes and produced the antibiotics 2,4-diacetylphloroglucinol, pyrrolnitrin, pyoluteorin and phenazines respectively. Six strains contained acdS, which encodes 1-aminocyclopropane-1-carboxylic acid deaminase. Phylogenetic analysis of 16S rDNA and phlD, phzF and acdS genes demonstrated that some strains identified as Pseudomonas were similar to model PGPR strains Pseudomonas protegens Pf-5, Pseudomonas chlororaphis subsp. aureofaciens 30-84 and P. brassicacearum Q8r1-96. Pseudomonas protegens- and P. chlororaphis-like strains had the greatest biocontrol activity against Rhizoctonia root rot and take-all of wheat. Pseudomonas protegens and P. brassicacearum-like strains showed the greatest promotion of canola growth. Our results indicate that strains from contaminated soils are similar to well-described PGPR found in agricultural soils worldwide.
Topics: Antibiosis; Antifungal Agents; Bacteria; Bacterial Proteins; China; Cluster Analysis; DNA, Bacterial; DNA, Ribosomal; Environmental Pollution; Humans; Molecular Sequence Data; Nerve Growth Factors; Pest Control, Biological; Phylogeny; Plant Development; Plant Diseases; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil Microbiology
PubMed: 25219642
DOI: 10.1111/1751-7915.12158 -
Biomedical Papers of the Medical... Sep 2014Screening of bacterial flora for strains producing metabolites with inhibitory effects on the human pathogenic oomycete Pythium insidiosum. Separation and...
AIMS
Screening of bacterial flora for strains producing metabolites with inhibitory effects on the human pathogenic oomycete Pythium insidiosum. Separation and characterization of extracts from Pseudomonas stutzeri with anti-Pythium inhibitory activity. Search for genes with anti-Pythium effect within the genome of P. stutzeri.
METHODS
A total of 88 bacterial strains were isolated from water resources in northeastern Thailand. Two screening methods were used to establish their inhibitory effects on P. insidiosum. One strain, P. stutzeri ST1302 was randomly chosen, and the extract with anti-P. insidiosum activity was fractionated and subfractionated using liquid column chromatography and purified by thin layer chromatography. The chemical structure of purified fractions was determined by Fourier transform infrared spectroscopy, nuclear magnetic resonance and mass spectrometry. Further, search for genes involved in the anti-Pythium activity (phenazine-1-carboxylic acid, 2,4-diacetylphloroglucinol, pyoluteorin and pyrrolnitrin) was undertaken in this P. stutzeri strain using primers described in the literature.
RESULTS
Anti-P. insidiosum activity was detected in 16 isolates (18.2%). In P. stutzeri ST1302, a subfraction labeled PYK7 exhibited strong activity against this oomycete. It was assigned to the diketopiperazines as cyclo(D-Pro-L-Val). In the search for genes, one gene region was successfully amplified. This corresponded to pyrrolnitrin. The results suggest the possibility of using the related metabolites against P. insidiosum. This is the first report on the inhibitory effects of P. stutzeri against this oomycete. The results may contribute to the development of antimicrobial drugs/probiotics against pythiosis.
Topics: Diketopiperazines; Genome, Bacterial; Microbial Sensitivity Tests; Pseudomonas stutzeri; Pyrrolnitrin; Pythiosis; Pythium; Thailand
PubMed: 23149469
DOI: 10.5507/bp.2012.090