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In vivo gene expression of Pseudomonas putida KT2440 in the rhizosphere of different plants.

Fernández M, Conde S, Duque E, Ramos JL - Microb Biotechnol (2013)

Bottom Line: Using the IVET technology we investigated which KT2440 genes were expressed in the rhizosphere of four different plants: pine, cypress, evergreen oak and rosemary.Another 40 fusions were found to correspond to likely promoters that encode antisense RNAs of unknown function, some of which were isolated as fusions from the bacteria recovered in the rhizosphere from all of the plants, while others were specific to one or several of the plants.The results obtained in this study suggest that plant-specific signals are sensed by KT2440 in the rhizosphere and that the signals and consequent gene expression are related to the bacteria's successful establishment in this niche.

View Article: PubMed Central - PubMed

Affiliation: Bio-Iliberis Research and Development, I+D Department, 18210, Peligros, Granada, Spain.

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Population size after 2 months in the rhizosphere of P. putida △asd with pOR1 and different transcriptional fusions in pine and cypress. pOR1: plasmid without insert (negative control); pOR1:fusP2431, transcriptional fusion of the asd to the PP2431 promoter, pOR1:fusP3689, transcriptional fusion of the asd to PP3689 promoter, and pOR1:fusP0340, transcriptional fusion the asd with the PP0340 promoter. Population sizes were determined by plate counting in minimal medium supplemented with kanamycin, DAP and amino acids. Experiments were run in triplicate. Transcriptional fusions to verify were chosen at random, error bars show the standard error.
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fig03: Population size after 2 months in the rhizosphere of P. putida △asd with pOR1 and different transcriptional fusions in pine and cypress. pOR1: plasmid without insert (negative control); pOR1:fusP2431, transcriptional fusion of the asd to the PP2431 promoter, pOR1:fusP3689, transcriptional fusion of the asd to PP3689 promoter, and pOR1:fusP0340, transcriptional fusion the asd with the PP0340 promoter. Population sizes were determined by plate counting in minimal medium supplemented with kanamycin, DAP and amino acids. Experiments were run in triplicate. Transcriptional fusions to verify were chosen at random, error bars show the standard error.

Mentions: Although most of the transcriptional fusions were isolated several times from independent samples, we performed an additional set of assays to verify that the isolated clones indeed exhibited asd expression in the rhizosphere from the promoters cloned in the transcriptional fusions. With this aim we randomly chose clones containing a transcriptional fusion found in all plants or only in some of the plants and carried out rhizosphere colonization assays with pure cultures of these clones. The results were compared with those obtained with P. putida Δasd carrying pOR1 (without insert). In all cases, clones with transcriptional fusions kept their population sizes at a level that was at least three orders of magnitude higher than P. putida Δasd with the empty plasmid (Fig. 3). When clones with transcriptional fusions found in only one type of plant were tested in the rhizosphere of another plant, differences in the cell densities were significant, around two orders of magnitude of variation (Table 2).


In vivo gene expression of Pseudomonas putida KT2440 in the rhizosphere of different plants.

Fernández M, Conde S, Duque E, Ramos JL - Microb Biotechnol (2013)

Population size after 2 months in the rhizosphere of P. putida △asd with pOR1 and different transcriptional fusions in pine and cypress. pOR1: plasmid without insert (negative control); pOR1:fusP2431, transcriptional fusion of the asd to the PP2431 promoter, pOR1:fusP3689, transcriptional fusion of the asd to PP3689 promoter, and pOR1:fusP0340, transcriptional fusion the asd with the PP0340 promoter. Population sizes were determined by plate counting in minimal medium supplemented with kanamycin, DAP and amino acids. Experiments were run in triplicate. Transcriptional fusions to verify were chosen at random, error bars show the standard error.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3815925&req=5

fig03: Population size after 2 months in the rhizosphere of P. putida △asd with pOR1 and different transcriptional fusions in pine and cypress. pOR1: plasmid without insert (negative control); pOR1:fusP2431, transcriptional fusion of the asd to the PP2431 promoter, pOR1:fusP3689, transcriptional fusion of the asd to PP3689 promoter, and pOR1:fusP0340, transcriptional fusion the asd with the PP0340 promoter. Population sizes were determined by plate counting in minimal medium supplemented with kanamycin, DAP and amino acids. Experiments were run in triplicate. Transcriptional fusions to verify were chosen at random, error bars show the standard error.
Mentions: Although most of the transcriptional fusions were isolated several times from independent samples, we performed an additional set of assays to verify that the isolated clones indeed exhibited asd expression in the rhizosphere from the promoters cloned in the transcriptional fusions. With this aim we randomly chose clones containing a transcriptional fusion found in all plants or only in some of the plants and carried out rhizosphere colonization assays with pure cultures of these clones. The results were compared with those obtained with P. putida Δasd carrying pOR1 (without insert). In all cases, clones with transcriptional fusions kept their population sizes at a level that was at least three orders of magnitude higher than P. putida Δasd with the empty plasmid (Fig. 3). When clones with transcriptional fusions found in only one type of plant were tested in the rhizosphere of another plant, differences in the cell densities were significant, around two orders of magnitude of variation (Table 2).

Bottom Line: Using the IVET technology we investigated which KT2440 genes were expressed in the rhizosphere of four different plants: pine, cypress, evergreen oak and rosemary.Another 40 fusions were found to correspond to likely promoters that encode antisense RNAs of unknown function, some of which were isolated as fusions from the bacteria recovered in the rhizosphere from all of the plants, while others were specific to one or several of the plants.The results obtained in this study suggest that plant-specific signals are sensed by KT2440 in the rhizosphere and that the signals and consequent gene expression are related to the bacteria's successful establishment in this niche.

View Article: PubMed Central - PubMed

Affiliation: Bio-Iliberis Research and Development, I+D Department, 18210, Peligros, Granada, Spain.

Show MeSH
Related in: MedlinePlus