Production of 2,4-diacetylphloroglucinol by the biocontrol agent <i>Pseudomonas fluorescens</i> Pf-5

Nowak-Thompson, Brian; Gould, Steven J.; Kraus, J.; Loper, Joyce E.

doi:10.1139/m94-168

Cited by 179 publications

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“…Many Pseudomonas fluorescens strains produce 2,4-diacetylphloroglucinol (PHL) (Bangera & Thomashow, 1996;Boruah & Kumar, 2002;Nowak-Thompson et al, 1994;Reddi & Borovkov, 1970; Sharifi-Tehrani et al, 1998). This phenolic molecule has broad-spectrum antifungal (Levy et al, 1992;Schoonbeek et al, 2002;Tomas-Lorente et al, 1989;Weller & Cook, 1983), antibacterial (Levy et al, 1992), antihelminthic (Bowden et al, 1965; Harrison et al, 1993) and phytotoxic (Keel et al, 1992;Reddi et al, 1969) activities.…”

Section: Introductionmentioning

confidence: 99%

The putative permease PhlE of Pseudomonas fluorescens F113 has a role in 2,4-diacetylphloroglucinol resistance and in general stress tolerance

et al. 2004

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2,4-Diacetylphloroglucinol (PHL) is the primary determinant of the biological control activity of Pseudomonas fluorescens F113. The operon phlACBD encodes enzymes responsible for PHL biosynthesis from intermediate metabolites. The phlE gene, which is located downstream of the phlACBD operon, encodes a putative permease suggested to be a member of the major facilitator superfamily with 12 transmembrane segments. PhlE has been suggested to function in PHL export. Here the sequencing of the phlE gene from P. fluorescens F113 and the construction of a phlE null mutant, F113-D3, is reported. It is shown that F113-D3 produced less PHL than F113. The ratio of cell-associated to free PHL was not significantly different between the strains, suggesting the existence of alternative transporters for PHL. The phlE mutant was, however, significantly more sensitive to high concentrations of added PHL, implicating PhlE in PHL resistance. Furthermore, the phlE mutant was more susceptible to osmotic, oxidative and heat-shock stresses. Osmotic stress induced rapid degradation of free PHL by the bacteria. Based on these results, we propose that the role of phlE in general stress tolerance is to export toxic intermediates of PHL degradation from the cells. INTRODUCTIONMany Pseudomonas fluorescens strains produce 2,4-diacetylphloroglucinol (PHL) (Bangera & Thomashow, 1996;Boruah & Kumar, 2002;Nowak-Thompson et al., 1994;Reddi & Borovkov, 1970; Sharifi-Tehrani et al., 1998). This phenolic molecule has broad-spectrum antifungal (Levy et al., 1992;Schoonbeek et al., 2002;Tomas-Lorente et al., 1989;Weller & Cook, 1983), antibacterial (Levy et al., 1992), antihelminthic (Bowden et al., 1965; Harrison et al., 1993) and phytotoxic (Keel et al., 1992;Reddi et al., 1969) activities. PHL is the primary determinant of biological control by P. fluorescens F113 (Shanahan et al., 1992). Synthesis of PHL is directed by the phlACBD genes, which are believed to constitute an operon (Bangera & Thomashow, 1996Delany, 1999). PhlD shows structural similarities with plant chalcone synthase, also called polyketide synthase type III, and is necessary but not sufficient for the synthesis of monoacetylphloroglucinol (MAPG) (Bangera & Thomashow, 1999). PhlA, PhlC and PhlB are necessary and sufficient for the transacetylation of MAPG to produce PHL (Bangera & Thomashow, 1999;Shanahan et al., 1992). The available data strongly suggest that PhlA, PhlC, PhlB and PhlD function in a multienzyme complex (Bangera & Thomashow, 1999;Delany, 1999). Expression of the phlACBD operon is subject to complex regulation (Aarons et al., 2000;Abbas et al., 2002;Bangera & Thomashow, 1999;Chou et al., 1993;Corbell & Loper, 1995;Delany, 1999; Delany et al., 2000;Duffy & Defago, 1999;Schnider-Keel et al., 2000). In addition, PHL is an autoregulator, positively influencing its own biosynthesis (Abbas et al., 2002;Schnider-Keel et al., 2000).Micro-organisms have developed various ways to resist the toxic effects of the secondary metabolites they produce. These mechanisms include expo...

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Section: Introductionmentioning

confidence: 99%

The putative permease PhlE of Pseudomonas fluorescens F113 has a role in 2,4-diacetylphloroglucinol resistance and in general stress tolerance

et al. 2004

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“…These products include chlorinated nonribosomal peptides such as the vancomycin and teicoplanin family of glycopeptides (2) and aromatic polyketides such as chlorotetracycline (3). Most of the organochlorine linkages are in aromatic or heteroaromatic rings, such as the 3-Cl-␤-OH-Tyr of the glycopeptides, the chloro substituent in the aminocoumarin antibiotics (2)(3)(4), and the 4,5-dichloropyrrole in pyoluteorin (5) (Fig. 1A).…”

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confidence: 99%

SyrB2 in syringomycin E biosynthesis is a nonheme Fe ^II α-ketoglutarate- and O ₂ -dependent halogenase

Vaillancourt

Yin

Walsh

2005

Proc. Natl. Acad. Sci. U.S.A.

321

354

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“…4A). Interestingly, PfY and PfZ clustered close to each other and to phlD genes found in BOX genotype A strains CHA0 [10] and Pf-5 [33]. Also, analysis of the deduced protein sequences revealed that phlD from PfY and PfZ isolates are different from known PhlD sequences and closely related to those from strains CHA0 and Pf-5 (data not shown).…”

Section: Resultsmentioning

confidence: 82%

Wheat Cultivar-Specific Selection of 2,4-Diacetylphloroglucinol-Producing Fluorescent Pseudomonas Species from Resident Soil Populations

Mazzola¹,

2004

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An emerging body of evidence indicates a role for plant genotype as a determinant of the species and genetic composition of the saprophytic microbial community resident to the rhizosphere. In this study, experiments were conducted to determine the capacity of five different wheat cultivars to enhance resident populations and support introduced strains of 2,4-diacetylphloroglucinol (2,4-DAPG)-producing fluorescent pseudomonads, a group of bacteria known to provide biological control of several soilborne diseases. When soils were cropped with three successive 28-day growth cycles of wheat, the 2,4-DAPG-producing strains were consistently recovered from the rhizosphere of the cultivar Lewjain, and commonly were present at populations higher than those recovered from other wheat cultivars. Based on restriction fragment length polymorphism and sequence analyses of phlD, a key gene involved in 2,4-DAPG production, two previously undefined phlD+ genotypes, referred to as genotypes PfZ and PfY, were discovered. Wheat cultivar Lewjain was the primary source of genotype PfY while cultivar Penawawa yielded the majority of genotype PfZ. Based on 16S rDNA sequence analysis, both new phlD genotypes were classified as P. fluorescens. Comparison of the rhizosphere competence of 2,4-DAPG-producing P. fluorescens Q2-87 (genotype B) and P. fluorescens LR3-A28 (genotype PfY) showed that both strains persisted at similar populations in the rhizosphere of all cultivars tested over a 30 day period when introduced as a seed inoculant. However, when strain LR3-A28 was applied as a soil inoculant, this strain was recovered at higher populations from the rhizosphere of wheat cultivar Lewjain than from the rhizospheres of two other cultivars. No cultivar effects were shown for strain Q2-87. Collectively, these results add further to evidence indicating a degree of specificity in interactions between plant cultivars and specific members of the saprophytic microbial community. Furthermore, as 2,4-DAPG-producing fluorescent Pseudomonas spp. have a central role in the spontaneous reduction in severity of take-all disease of wheat in response to continuous wheat monoculture, we postulate that the use of specific cultivars, such as Lewjain, which possess a superior capacity to enhance resident soil populations of these bacteria may have potential to reduce the length of the monoculture period required to induce natural suppressiveness of soils toward this disease.

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Production of 2,4-diacetylphloroglucinol by the biocontrol agent Pseudomonas fluorescens Pf-5

Cited by 179 publications

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The putative permease PhlE of Pseudomonas fluorescens F113 has a role in 2,4-diacetylphloroglucinol resistance and in general stress tolerance

The putative permease PhlE of Pseudomonas fluorescens F113 has a role in 2,4-diacetylphloroglucinol resistance and in general stress tolerance

SyrB2 in syringomycin E biosynthesis is a nonheme Fe ^II α-ketoglutarate- and O ₂ -dependent halogenase

Wheat Cultivar-Specific Selection of 2,4-Diacetylphloroglucinol-Producing Fluorescent Pseudomonas Species from Resident Soil Populations

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Production of 2,4-diacetylphloroglucinol by the biocontrol agent Pseudomonas fluorescens Pf-5

Cited by 179 publications

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The putative permease PhlE of Pseudomonas fluorescens F113 has a role in 2,4-diacetylphloroglucinol resistance and in general stress tolerance

The putative permease PhlE of Pseudomonas fluorescens F113 has a role in 2,4-diacetylphloroglucinol resistance and in general stress tolerance

SyrB2 in syringomycin E biosynthesis is a nonheme Fe II α-ketoglutarate- and O 2 -dependent halogenase

Wheat Cultivar-Specific Selection of 2,4-Diacetylphloroglucinol-Producing Fluorescent Pseudomonas Species from Resident Soil Populations

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SyrB2 in syringomycin E biosynthesis is a nonheme Fe ^II α-ketoglutarate- and O ₂ -dependent halogenase