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Sharifi-Tehrani, A; Zala, Marcello; Natsch, Andreas; Moënne‐Loccoz, Yvan; Défago, Geneviève

doi:10.1023/a:1008672104562

Cited by 125 publications

(9 citation statements)

References 47 publications

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“…Strain Pf-5 is a model biological control agent that inhabits the rhizosphere of plants and suppresses diseases caused by a wide variety of soilborne pathogens [3-15]. The original analysis of the Pf-5 genome [3] focused primarily on the strain's metabolic capacity and on the pathways involved in the production of secondary metabolites.…”

Section: Introductionmentioning

confidence: 99%

Mobile genetic elements in the genome of the beneficial rhizobacterium Pseudomonas fluorescens Pf-5

et al. 2009

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BackgroundPseudomonas fluorescens Pf-5 is a plant-associated bacterium that inhabits the rhizosphere of a wide variety of plant species and and produces secondary metabolites suppressive of fungal and oomycete plant pathogens. The Pf-5 genome is rich in features consistent with its commensal lifestyle, and its sequence has revealed attributes associated with the strain's ability to compete and survive in the dynamic and microbiologically complex rhizosphere habitat. In this study, we analyzed mobile genetic elements of the Pf-5 genome in an effort to identify determinants that might contribute to Pf-5's ability to adapt to changing environmental conditions and/or colonize new ecological niches.ResultsSequence analyses revealed that the genome of Pf-5 is devoid of transposons and IS elements and that mobile genetic elements (MGEs) are represented by prophages and genomic islands that collectively span over 260 kb. The prophages include an F-pyocin-like prophage 01, a chimeric prophage 03, a lambdoid prophage 06, and decaying prophages 02, 04 and 05 with reduced size and/or complexity. The genomic islands are represented by a 115-kb integrative conjugative element (ICE) PFGI-1, which shares plasmid replication, recombination, and conjugative transfer genes with those from ICEs found in other Pseudomonas spp., and PFGI-2, which resembles a portion of pathogenicity islands in the genomes of the plant pathogens Pseudomonas syringae and P. viridiflava. Almost all of the MGEs in the Pf-5 genome are associated with phage-like integrase genes and are integrated into tRNA genes.ConclusionComparative analyses reveal that MGEs found in Pf-5 are subject to extensive recombination and have evolved in part via exchange of genetic material with other Pseudomonas spp. having commensal or pathogenic relationships with plants and animals. Although prophages and genomic islands from Pf-5 exhibit similarity to MGEs found in other Pseudomonas spp., they also carry a number of putative niche-specific genes that could affect the survival of P. fluorescens Pf-5 in natural habitats. Most notable are a ~35-kb segment of "cargo" genes in genomic island PFGI-1 and bacteriocin genes associated with prophages 1 and 4.

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Section: Introductionmentioning

confidence: 99%

Mobile genetic elements in the genome of the beneficial rhizobacterium Pseudomonas fluorescens Pf-5

et al. 2009

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“…have been extensively studied for their ability to protect plants from pathogenic fungi and oomycetes (16), but fewer studies have focused on their ability to suppress bacterial pathogens. Clavibacter michiganensis subsp.…”

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confidence: 99%

Interaction between 2,4-Diacetylphloroglucinol- and Hydrogen Cyanide-Producing Pseudomonas brassicacearum LBUM300 and Clavibacter michiganensis subsp. michiganensis in the Tomato Rhizosphere

Paulin

Novinscak

Lanteigne

et al. 2017

Appl Environ Microbiol

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We have previously demonstrated that inoculation of tomato plants with 2,4-diacetylphloroglucinol (DAPG)-and hydrogen cyanide (HCN)-producing Pseudomonas brassicacearum LBUM300 could significantly reduce bacterial canker symptoms caused by Clavibacter michiganensis subsp. michiganensis. In this study, in order to better characterize the population dynamics of LBUM300 in the rhizosphere of tomato plants, we characterized the role played by DAPG and HCN production by LBUM300 on rhizosphere colonization of healthy and C. michiganensis subsp. michiganensis-infected tomato plants. The impact of C. michiganensis subsp. michiganensis presence on the expression of DAPG and HCN biosynthetic genes in the rhizosphere was also examined. In planta assays were performed using combinations of C. michiganensis subsp. michiganensis and wild-type LBUM300 or DAPG (LBUM300ΔphlD) or HCN (LBUM300ΔhcnC) isogenic mutant strains. Populations of LBUM300 and phlD and hcnC gene expression levels were quantified in rhizosphere soil at several time points up to 264 h postinoculation using culture-independent quantitative PCR (qPCR) and reverse transcriptase quantitative PCR (RT-qPCR) TaqMan assays, respectively. The presence of C. michiganensis subsp. michiganensis significantly increased rhizospheric populations of LBUM300. In C. michiganensis subsp. michiganensis-infected tomato rhizospheres, the populations of wild-type LBUM300 and strain LBUM300ΔhcnC, both producing DAPG, were significantly higher than the population of strain LBUM300ΔphlD. A significant upregulation of phlD expression was observed in the presence of C. michiganensis subsp. michiganensis, while hcnC expression was only slightly increased in the mutant strain LBUM300ΔphlD when C. michiganensis subsp. michiganensis was present. Additionally, biofilm production was found to be significantly reduced in strain LBUM300ΔphlD compared to the wild-type and LBUM300ΔhcnC strains. IMPORTANCEThe results of this study suggest that C. michiganensis subsp. michiganensis infection of tomato plants contributes to increasing rhizospheric populations of LBUM300, a biocontrol agent, as well as the overexpression of the DAPG biosynthetic operon in this bacterium. The increasing rhizospheric populations of LBUM300 represent one of the key factors in controlling C. michiganensis subsp. michiganensis in tomato plants, as DAPG-producing bacteria have shown the ability to decrease bacterial canker symptoms in tomato plants. KEYWORDS Clavibacter michiganensis, DAPG, HCN, Pseudomonas, gene expression, rhizosphere, tomato

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“…Among the strains of Pseudomonas spp. effective in biological control are P. protegens Pf-5 and the closely related strain P. protegens CHA0 (30). These strains of P. protegens produce a nearly identical spectrum of antibiotics, with the exception of the rhizoxin analogs, which are produced by Pf-5 but not by CHA0.…”

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confidence: 99%

An Interspecies Signaling System Mediated by Fusaric Acid Has Parallel Effects on Antifungal Metabolite Production by Pseudomonas protegens Strain Pf-5 and Antibiosis of Fusarium spp

Quecine

Kidarsa

Goebel

et al. 2016

Appl Environ Microbiol

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dPseudomonas protegens strain Pf-5 is a rhizosphere bacterium that suppresses soilborne plant diseases and produces at least seven different secondary metabolites with antifungal properties. We derived mutants of Pf-5 with single and multiple mutations in biosynthesis genes for seven antifungal metabolites: 2,4-diacetylphoroglucinol (DAPG), pyrrolnitrin, pyoluteorin, hydrogen cyanide, rhizoxin, orfamide A, and toxoflavin. These mutants were tested for inhibition of the pathogens Fusarium verticillioides and Fusarium oxysporum f. sp. pisi. Rhizoxin, pyrrolnitrin, and DAPG were found to be primarily responsible for fungal antagonism by Pf-5. Previously, other workers showed that the mycotoxin fusaric acid, which is produced by many Fusarium species, including F. verticillioides, inhibited the production of DAPG by Pseudomonas spp. In this study, amendment of culture media with fusaric acid decreased DAPG production, increased pyoluteorin production, and had no consistent influence on pyrrolnitrin or orfamide A production by Pf-5. Fusaric acid also altered the transcription of biosynthetic genes, indicating that the mycotoxin influenced antibiotic production by Pf-5 at the transcriptional level. Addition of fusaric acid to the culture medium reduced antibiosis of F. verticillioides by Pf-5 and derivative strains that produce DAPG but had no effect on antibiosis by Pf-5 derivatives that suppressed F. verticillioides due to pyrrolnitrin or rhizoxin production. Our results demonstrated the importance of three compounds, rhizoxin, pyrrolnitrin, and DAPG, in suppression of Fusarium spp. by Pf-5 and confirmed that an interspecies signaling system mediated by fusaric acid had parallel effects on antifungal metabolite production and antibiosis by the bacterial biological control organism. Pseudomonas is a heterogeneous genus of Gammaproteobacteria composed of species with diverse ecological roles; certain strains are members of the plant microbiome contributing to plant growth and health. Our studies focus on the soil bacterium Pseudomonas protegens Pf-5, which is known for its capacity to suppress plant diseases and produce a large spectrum of metabolites with antibiotic activity (1, 2). The antibiotics produced by Pf-5 include pyrrolnitrin (3), pyoluteorin (4), analogs of rhizoxin (5, 6), hydrogen cyanide (7), 2,4-diacetylphloroglucinol (DAPG) (8), monoacetylphloroglucinol (MAPG) (9) (an intermediate in the DAPG biosynthetic pathway [10,11]), the lipopeptide orfamide A (12), and toxoflavin (13). The antibiotics produced by Pf-5 have distinct but overlapping activity spectra, and it is likely that multiple compounds contribute to the interactions of Pf-5 with target plant pathogens that result in disease suppression. Commonly, the role of an antibiotic in biological control is assessed by comparing the level of disease suppression provided by a wild-type strain versus an antibiotic-deficient mutant (14). For strain Pf-5, however, this approach has not been highly successful in providing evidence for the roles of antibioti...

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Cited by 125 publications

References 47 publications

Mobile genetic elements in the genome of the beneficial rhizobacterium Pseudomonas fluorescens Pf-5

Mobile genetic elements in the genome of the beneficial rhizobacterium Pseudomonas fluorescens Pf-5

Interaction between 2,4-Diacetylphloroglucinol- and Hydrogen Cyanide-Producing Pseudomonas brassicacearum LBUM300 and Clavibacter michiganensis subsp. michiganensis in the Tomato Rhizosphere

An Interspecies Signaling System Mediated by Fusaric Acid Has Parallel Effects on Antifungal Metabolite Production by Pseudomonas protegens Strain Pf-5 and Antibiosis of Fusarium spp

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