A5042933034- Plant-Microbe Interactions and Immunity
- Legume Nitrogen Fixing Symbiosis
- Plant Pathogenic Bacteria Studies
- Plant Disease Resistance and Genetics
- Microbial Community Ecology and Physiology
- Plant Pathogens and Fungal Diseases
- Microbial Natural Products and Biosynthesis
- Plant tissue culture and regeneration
- Nematode management and characterization studies
- Genomics and Phylogenetic Studies
- Bacterial Genetics and Biotechnology
- Bacterial biofilms and quorum sensing
- Plant Disease Management Techniques
- Mycorrhizal Fungi and Plant Interactions
- Plant Pathogens and Resistance
- Bacteriophages and microbial interactions
- Genetically Modified Organisms Research
- Plant Virus Research Studies
- Soil Carbon and Nitrogen Dynamics
- Mycotoxins in Agriculture and Food
- Plant Parasitism and Resistance
- Enzyme Structure and Function
- Wheat and Barley Genetics and Pathology
- Antibiotic Resistance in Bacteria
- Heavy metals in environment
Agricultural Research Service
2016-2025
Quality Research
2016-2025
Washington State University
2013-2024
United States Department of Agriculture
2015-2024
Agricultural Research Service - Pacific West Area
2022
United States Department of State
2019
University of Southern Mississippi
2014-2018
University of Minnesota
2017
Gustavus Adolphus College
2017
Malaysian Cocoa Board
2016-2017
Pseudomonas fluorescens 2-79 (NRRL B-15132) and its rifampin-resistant derivative 2-79RN10 are suppressive to take-all, a major root disease of wheat caused by Gaeumannomyces graminis var. tritici. Strain produces the antibiotic phenazine-1-carboxylate, which is active in vitro against G. tritici other fungal pathogens. Mutants defective phenazine synthesis (Phz-) were generated Tn5 insertion then compared with parental strain determine importance take-all suppression on roots. Six...
Two seven-gene phenazine biosynthetic loci were cloned from Pseudomonas aeruginosa PAO1. The operons, designated phzA1B1C1D1E1F1G1 and phzA2B2C2D2E2F2G2, are homologous to previously studied operons fluorescens aureofaciens. Functional studies of phenazine-nonproducing strains fluorescent pseudomonads indicated that each the P. is sufficient for production a single compound, phenazine-1-carboxylic acid (PCA). Subsequent conversion PCA pyocyanin mediated in by two novel phenazine-modifying...
Pseudomonas fluorescens Pf-5 is a plant commensal bacterium that inhabits the rhizosphere and produces secondary metabolites suppress soilborne pathogens. The complete sequence of 7.1-Mb genome was determined. We analyzed repeat sequences to identify genomic islands that, together with other approaches, suggested P. Pf-5's recent lateral acquisitions include six metabolite gene clusters, seven phage regions mobile island. identified various features contribute its lifestyle on plants,...
We provide here a comparative genome analysis of ten strains within the Pseudomonas fluorescens group including seven new genomic sequences. These exhibit diverse spectrum traits involved in biological control and other multitrophic interactions with plants, microbes, insects. Multilocus sequence placed three sub-clades, which was reinforced by high levels synteny, size core genomes, relatedness orthologous genes between sub-clade. The heterogeneity P. reflected large its pan-genome, makes...
The antibiotics phenazine-1-carboxylic acid (PCA) and 2,4-diacetylphloroglucinol (Phl) are major determinants of biological control soilborne plant pathogens by various strains fluorescent Pseudomonas spp. In this study, we described primers probes that enable specific efficient detection a wide variety produce phenazine or Phl. PCR analysis Southern hybridization demonstrated genes within the biosynthetic loci for Phl PCA conserved among worldwide origin. frequency Phl- PCA-producing...
Soils suppressive to soilborne pathogens have been identified worldwide for almost 60 years and attributed mainly or antagonistic microorganisms. Rather than identifying, testing applying potential biocontrol agents in an inundative fashion, research into soils has attempted understand how indigenous microbiomes can reduce disease, even the presence of pathogen, susceptible host, favorable environment. Recent advances next-generation sequencing provided new tools reexamine further...
Pseudomonas fluorescens 2-79 and P. aureofaciens 30-84 produce the antibiotic phenazine-1-carboxylic acid suppress take-all, an important root disease of wheat caused by Gaeumannomyces graminis var. tritici. To determine whether is produced in situ, seeds were treated with strain or phenazine-nonproducing mutants left untreated then sown natural steamed soil field growth chamber. The was isolated only from roots colonized both chamber studies. No recovered seedlings grown untreated. In...
Genetic resistance in plants to root diseases is rare, and agriculture depends instead on practices such as crop rotation soil fumigation control these diseases. "Induced suppression" a natural phenomenon whereby due microbiological changes converts from conducive suppressive soilborne pathogen during prolonged monoculture of the susceptible host. Our studies have focused wheat disease "take-all," caused by fungus Gaeumannomyces graminis var. tritici, role bacteria rhizosphere...
Phenazine antibiotics produced by Pseudomonas fluorescens 2-79 and aureofaciens 30-84, previously shown to be the principal factors enabling these bacteria suppress take-all of wheat caused Gaeumannomyces graminis var. tritici, also contribute ecological competence strains in soil rhizosphere wheat. Strains their Tn5 mutants defective phenazine production (Phz-), or mutant genetically restored for (Phz+) were introduced into Thatuna silt loam (TSL) TSL amended with G. tritici. Soils planted...
Abstract Background Process and function that underlie the assembly of a rhizosphere microbial community may be strongly linked to maintenance plant health. However, their processes functional changes in deterioration soilborne disease remain unclear. Here, we investigated features microbiomes related Fusarium wilt assessed by comparison pair diseased/healthy sequencing data. The untargeted metabolomics was employed explore potential drivers, shotgun metagenome used reveal mechanisms...
One model of a disease-suppressive soil predicts that the confrontation plant with phytopathogen can lead to recruitment and accumulation beneficial microorganisms. However, more information needs be deciphered regarding which microbes become enriched, how disease suppression is achieved. Here, we conditioned by continuously growing eight generations cucumber inoculated Fusarium oxysporum f.sp. cucumerinum in split-root system. Disease incidence was found decrease gradually upon pathogen...
ABSTRACT The polyketide metabolite 2,4-diacetylphloroglucinol (2,4-DAPG) is produced by many strains of fluorescent Pseudomonas spp. with biocontrol activity against soilborne fungal plant pathogens. Genes required for 2,4-DAPG synthesis P. fluorescens Q2-87 are encoded a 6.5-kb fragment genomic DNA that can transfer production to 2,4-DAPG-nonproducing recipient strains. In this study the nucleotide sequence was determined and flanking regions from strain Q2-87. Six open reading frames were...
The broad-spectrum antibiotic 2,4-diacetylphloroglucinol (PHL) is a major determinant in the biological control of range plant pathogens by many fluorescent Pseudomonas spp. A 4.8-kb chromosomal DNA region from fluorescens Q2-87, carrying PHL biosynthetic genes, was used as probe to determine if locus conserved within PHL-producing strains worldwide origin. phl gene hybridized with genomic all 45 tested, including well-characterized biocontrol United States and Europe isolated...
Stable incorporation of tumor-inducing (Ti) plasmid sequences, the T-DNA, into genomes dicotyledonous plants results in formation crown gall tumors. Previous genetic studies have suggested that products genes encoding transcripts 1 and 2, which are encoded by TL-DNA region pTiA6, responsible for inducing auxin-independent phenotype tissues. Here we report construction a plasmid, pMTlacT2, directs synthesis Mr 49,800 polypeptide transcript 2 gene. Cell-free extracts prepared from Escherichia...
ABSTRACT Pseudomonas fluorescens 2-79 produces the broad-spectrum antibiotic phenazine-1-carboxylic acid (PCA), which is active against a variety of fungal root pathogens. In this study, seven genes designated phzABCDEFG that are sufficient for synthesis PCA were localized within 6.8-kb Bgl II- Xba I fragment from phenazine biosynthesis locus strain 2-79. Polypeptides corresponding to all phz identified by analysis recombinant plasmids in T7 promoter/polymerase expression system. Products...
Pseudomonas aureofaciens strain 30-84 suppresses take-all disease of wheat caused by Gaeumannomyces graminis var. tritici. Three antibiotics, phenazine-1-carboxylic acid, 2-hydroxyphenazine-1-carboxylic and 2-hydroxyphenazine, were responsible for suppression. Tn5-induced mutants deficient in production one or more the antibiotics (Phz-) significantly less suppressive than parental strain. Cosmids pLSP259 pLSP282 from a genomic library restored phenazine fungal inhibition to 10 different...
Phenazines are versatile secondary metabolites of bacterial origin that function in biological control plant pathogens and contribute to the ecological fitness pathogenicity producing strains. In this study, we employed a collection 94 strains having various geographic, environmental, clinical origins study distribution evolution phenazine genes members genera Pseudomonas, Burkholderia, Pectobacterium, Brevibacterium, Streptomyces. Our results confirmed diversity producers revealed most them...