Survival of and plasmid stability in <i>Pseudomonas</i> and <i>Klebsiella</i> spp. introduced into agricultural drainage water

Trevors, J. T.; Elsas, Jan Dirk van; Starodub, M.E.; Overbeek, L.S. van

doi:10.1139/m89-110

Cited by 29 publications

(18 citation statements)

References 18 publications

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“…It has been shown that in E. coli (3), Aeromonas salmonicida (17), and Klebsiella spp. (28), the number of plasmids possessed by the cells also decreased dur- FIG. 11.…”

Section: Discussionmentioning

confidence: 95%

Survival Response and Rearrangement of Plasmid DNA of Lactococcus lactis during Long-Term Starvation

Kim

Park

Ren

et al. 2001

Appl Environ Microbiol

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The survival response of Lactococcus lactis during long-term starvation was investigated. The cells were cultured with different levels of glucose (the sole energy source) and either were kept in the resultant spent medium or transferred to fresh medium (without glucose) for up to 2 years. The survival of the cells during starvation was not dependent on the nature of transition phase, as expected, but on the nature of medium in which the cells were kept. The proliferation of cells, despite the apparent lack of glucose, could have been due to some cells being able to utilize the small amounts of peptides still present in the spent medium or to use energy sources provided by the breakup of dead cells. The 1-and 2-year-old cultures contained cells with vastly changed morphotypes. When these isolates were examined, it was revealed that the original plasmids present in the parent were rearranged in a certain way, and an entirely new plasmid was generated. Changes were also evident in the chromosomal DNA and in gene expression. Furthermore, all of the isolates exhibited a growth advantage relative to the parent cells when grown in energy-limiting media. When they were tested against different types of stresses, they exhibited a higher resistance against the bile salt and hydrogen peroxide stresses compared to the parent. Because of the similar changes observed in the 2-year-old isolates, a similar survival strategy may be operational in those cells that survive for that length of time.

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“…It has been shown that in E. coli (3), Aeromonas salmonicida (17), and Klebsiella spp. (28), the number of plasmids possessed by the cells also decreased dur- FIG. 11.…”

Section: Discussionmentioning

confidence: 95%

Survival Response and Rearrangement of Plasmid DNA of Lactococcus lactis during Long-Term Starvation

Kim

Park

Ren

et al. 2001

Appl Environ Microbiol

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“…Many studies have investigated the survival of introduced microorganisms and the persistence of GEMMOs in natural or model ecosystems such as soil microcosms [1,2,[4][5][6][7][8]. Pseudomonads are seen as prime candidates to be used as vehicles of biocontrol functions to protect the rhizosphere against deleterious pathogenic organisms.…”

Section: Introductionmentioning

confidence: 99%

Survival of genetically modified Pseudomonas fluorescens introduced into subtropical soil microcosms

Araujo

1994

FEMS Microbiology Ecology

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A genetically modified strain of Pseudomonas fluorescens and its parent showed grossly similar decline rates following introduction into subtropical clay and sandy soils. In unplanted clay soit at pH 6.9 and 25°C, population densities declined progressively from about 108 to 103 colony forming units (cfu) g−1 dry soil over 75 days, but in unplanted sandy soil the introduced populations could not be detected after 25 days. In clay soil at pH 8.7 or 4.7, or at environmental temperature, decay rates were enhanced as compared to those at pH 6.9 and 25°C. Counts of introduced strains in clay bulk soil and in rhizosphere and rhizoplane of maize suggested that the introduced bacteria competed well with the native bacteria, and colonized the roots at about 106 cfu g−1 dry root at 25°C, over 20 days. However, rhizoplane colonization was lower at environmental temperature. The decay rate of both strains was slower in planted than in unplanted sandy soil. The population densities in the rhizosphere and rhizoplane in the sandy soil were significantly lower than those in the clay soil. Both introduced strains colonized the maize roots in both soils, using seeds coated with bacteria in 1% carboxymethyl cellulose. Introduced cells were localized at different sites along the roots of plants developing in clay soil, with higher densities in the original (near the seeds) and root hair zones as compared to the intermediate zones. No significant difference was observed between the extent of root colonization of the genetically modified strain and its parent.

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“…The results indicate that inoculum level and/or nutrient amendment had a significant influence on the survival of CHA0‐Rif in lysimeter effluent water. Similarly, the addition of nutrients to microcosms prepared with agricultural drainage water had a positive effect on persistence of the rhizosphere isolate P. fluorescens R2f(RP4) inoculated at 6 log cells ml −1 [23]. Strain R2f(RP4) could still be detected in microcosms 1 year after inoculation [36].…”

Section: Discussionmentioning

confidence: 98%

“…In addition, leaching of nutrients may also influence the ecology of inoculants transported to groundwater level. In microcosm experiments, the addition of diluted Luria Bertani medium to agricultural drainage water influenced maintenance of plasmid RP4 in P. fluorescens R2f and survival of the strain [23].…”

Section: Introductionmentioning

confidence: 99%

Survival and cell culturability of biocontrol Pseudomonas fluorescens CHA0 in lysimeter effluent water and utilization of a deleterious genetic modification to study the impact of the strain on numbers of resident culturable bacteria

Hase

Moënne‐Loccoz

Défago³

2001

FEMS Microbiology Ecology

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Little is known on the behavior of soil‐inoculated biocontrol pseudomonads once they are transported to deeper soil layers and/or groundwater levels after a heavy rain. This issue was investigated in inoculated microcosms containing lysimeter effluent water, and experimental conditions mimicking a worse‐case scenario for potential bacterial dissemination were chosen. First, the survival of the polyketide‐producing biocontrol strain Pseudomonas fluorescens CHA0‐Rif was studied for 175 days at two inoculation levels in unamended and nutrient‐amended lysimeter effluent water, and its impact on numbers of resident culturable bacteria was determined. Cell numbers of CHA0‐Rif declined to 3–4 log cells ml−1 (at high inoculum level) or reached the detection limit or below (at low inoculum level) by day 175, without generating significant numbers of non‐culturable cells. At high inoculum level, strain CHA0‐Rif resulted durably (from day 50 to 175) in higher numbers of the total resident culturable bacteria when compared with the uninoculated control. This effect, which did not take place at low inoculum level or when nutrients had been added, contrasts with the transient ecological impact of the strain on rhizosphere bacterial populations in previous studies. Neither 2,4‐diacetylphloroglucinol nor pyoluteorin were found in the water using HPLC, and inoculation with CHA0‐Rif had no effect on the percentages of the total culturable aerobic bacteria sensitive to either antimicrobial polyketide on day 20. Second, the impact of CHA0‐Rif on numbers of resident culturable bacteria was compared with that of CHA0‐Rif(pME3424). Plasmid pME3424 carries an extra copy of the strain's rpoD gene (encoding sigma factor σ70). CHA0‐Rif(pME3424) disappeared within 50 days in the water, but had the same impact as CHA0‐Rif on the total number of resident culturable bacteria. This suggests that the impact of CHA0‐Rif took place at the early stages of the experiment and was probably linked to the release of nutrients by introduced cells during inoculant decline.

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Survival of and plasmid stability in Pseudomonas and Klebsiella spp. introduced into agricultural drainage water

Cited by 29 publications

References 18 publications

Survival Response and Rearrangement of Plasmid DNA of Lactococcus lactis during Long-Term Starvation

Survival Response and Rearrangement of Plasmid DNA of Lactococcus lactis during Long-Term Starvation

Survival of genetically modified Pseudomonas fluorescens introduced into subtropical soil microcosms

Survival and cell culturability of biocontrol Pseudomonas fluorescens CHA0 in lysimeter effluent water and utilization of a deleterious genetic modification to study the impact of the strain on numbers of resident culturable bacteria

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