Ion chromatographic analysis of nutrients in seed exudate for microbial colonisation

Casey, C.; O'Sullivan, Órla; O’Gara, Fergal; Glennon, Jeremy D.

doi:10.1016/s0021-9673(97)01297-1

Cited by 20 publications

(13 citation statements)

References 12 publications

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“…Some authors prefer not to sterilize seeds prior to the preparation of exudates to avoid washes with methanol or hypochlorite, which could potentially remove components from the exudate (Casey et al . ).…”

Section: How Can the Spermosphere Be Studied?mentioning

confidence: 97%

A review: what is the spermosphere and how can it be studied?

et al. 2015

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SummaryThe spermosphere is the zone surrounding seeds where interactions between the soil, microbial communities and germinating seeds take place. The concept of the spermosphere is usually only applied during germination sensu stricto. Despite the transient nature of this very small zone of soil around the germinating seed, the microbial activities which occur there may have longlasting impacts on plants. The spermosphere is indirectly characterized by either (i) seed exudates, which could be inhibitors or stimulators of microorganism growth or (ii) the composition of the microbiome on and around the germinating seeds. The microbial communities present in the spermosphere directly reflect that of the germination medium or are hostdependent and influenced quantitatively and qualitatively by host exudates. Despite its strong impact on the future development of plants, the spermosphere remains little studied. This can be explained by the technical difficulties related to characterizing this concept due to its short duration, small size and biomass, and the number and complexity of the interactions that take place. However, recent technical methods, such as metabolite profiling, combining phenotypic methods with DNA-and RNA-based methods, could be used to investigate seed exudates, microbial communities and their interactions with the soil environment.

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Section: How Can the Spermosphere Be Studied?mentioning

confidence: 97%

A review: what is the spermosphere and how can it be studied?

et al. 2015

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“…In the current work, specific catabolic traits were used to compare the 498 isolates of RCFP, as was done for resident culturable aerobic bacteria from soybeans inoculated with Bacillus cereus UW85 (16). A large proportion of the carbon substrates tested have been detected in the exudates of plants (including sugar beets) but under laboratory conditions (5,8,18,51). The capacity to assimilate D-xylose, a monomer of several plant cell polymers that is present in sugar beet seed exudates (5), was less frequent in RCFP from bulk soil than in those from three of the four treatments associated with roots (Table 4); this result indicates possible selection by the roots of D-xylose-assimilating strains.…”

Section: Fig 2 Diversity Of Rapd Profiles For 16 Isolates Randomly mentioning

confidence: 99%

Impact of 2,4-Diacetylphloroglucinol-Producing Biocontrol Strain Pseudomonas fluorescens F113 on Intraspecific Diversity of Resident Culturable Fluorescent Pseudomonads Associated with the Roots of Field-Grown Sugar Beet Seedlings

Moënne‐Loccoz

Tichy²,

O'Donnell

et al. 2001

Appl Environ Microbiol

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The impact of the 2,4-diacetylphloroglucinol-producing biocontrol agent Pseudomonas fluorescens F113Rif on the diversity of the resident community of culturable fluorescent pseudomonads associated with the roots of field-grown sugar beet seedlings was evaluated. At 19 days after sowing, the seed inoculant F113Rif had replaced some of the resident culturable fluorescent pseudomonads at the rhizoplane but had no effect on the number of these bacteria in the rhizosphere. A total of 498 isolates of resident fluorescent pseudomonads were obtained and characterized by molecular means at the level of broad phylogenetic groups (by amplified ribosomal DNA restriction analysis) and at the strain level (with random amplified polymorphic DNA markers) as well as phenotypically (55 physiological tests). The introduced pseudomonad induced a major shift in the composition of the resident culturable fluorescent Pseudomonas community, as the percentage of rhizoplane isolates capable of growing on three carbon substrates (erythritol, adonitol, and L-tryptophan) not assimilated by the inoculant was increased from less than 10% to more than 40%. However, the pseudomonads selected did not display enhanced resistance to 2,4-diacetylphloroglucinol. The shift in the resident populations, which was spatially limited to the surface of the root (i.e., the rhizoplane), took place without affecting the relative proportions of phylogenetic groups or the high level of strain diversity of the resident culturable fluorescent Pseudomonas community. These results suggest that the root-associated Pseudomonas community of sugar beet seedlings is resilient to the perturbation that may be caused by a taxonomically related inoculant.

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“…Phloroglucinol production of the F113-phlF − mutant was compared to F113 in two alternative media : in minimal medium with succinate as sole carbon source, known to be repressive for phloroglucinol production (Dunne et al, 1996), and seed exudate medium, a complex medium reflective of the nutrients available in the rhizosphere of sugar beet (Casey et al, 1998). After 20 h growth in seed exudate medium, phloroglucinol amended with 100 µM FeCl 3 .…”

Section: Phloroglucinol Production Is Derepressed On Mutation Of Phlfmentioning

confidence: 99%

Regulation of production of the antifungal metabolite 2,4-diacetylphloroglucinol in Pseudomonas fluorescens F113: genetic analysis of phlF as a transcriptional repressor The GenBank accession number for the sequence reported in this paper is AF129856.

et al. 2000

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The antifungal metabolite 2,4-diacetylphloroglucinol plays a major role in the biocontrol capabilities of Pseudomonas fluorescens. The phloroglucinol biosynthetic locus of P. fluorescens F113 has been isolated previously. From nucleotide sequence data, a putative regulator gene (phlF) was identified upstream and divergently transcribed from the phlACBD phloroglucinol biosynthetic genes. PhlF shows similarity to various transcriptional repressors in the EMBL database and exhibits a helix-turn-helix motif in its amino acid sequence. phlF was cloned into an expression vector and the PhlF protein product was purified. Gel retardation experiments demonstrated PhlF to be a DNA-binding protein and showed that it binds to the phlA-phlF intergenic region. Introduction of phlF into P. fluorescens F113 in multiple copies resulted in repression of phloroglucinol production in this strain. This effect was mediated at the transcription level since the expression of a phloroglucinol biosynthetic gene fusion in this background was equally repressed. Furthermore, the inactivation of phlF results in derepression of phloroglucinol production in this strain.

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Ion chromatographic analysis of nutrients in seed exudate for microbial colonisation

Cited by 20 publications

References 12 publications

A review: what is the spermosphere and how can it be studied?

A review: what is the spermosphere and how can it be studied?

Impact of 2,4-Diacetylphloroglucinol-Producing Biocontrol Strain Pseudomonas fluorescens F113 on Intraspecific Diversity of Resident Culturable Fluorescent Pseudomonads Associated with the Roots of Field-Grown Sugar Beet Seedlings

Regulation of production of the antifungal metabolite 2,4-diacetylphloroglucinol in Pseudomonas fluorescens F113: genetic analysis of phlF as a transcriptional repressor The GenBank accession number for the sequence reported in this paper is AF129856.

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