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Pseudomonas putida strain PCL1444, selected for efficient root colonization and naphthalene degradation, effectively
Irene Kuiper1, Lev V Kravchenko, Guido V Bloemberg
1Leiden University, Institute of Molecular Plant Sciences, Clusius Laboratory, The Netherlands. kuiper@rulbim.leidenuniv.nl
Molecular Plant-Microbe Interactions : MPMI
|July 18, 2002
Summary
Rhizoremediation of naphthalene pollution is enhanced by the plant-bacterium pair Barmultra and Pseudomonas putida PCL1444. This is due to efficient root colonization and high transcription of naphthalene degradation genes on major root exudate components like glucose and succinic acid.
Area of Science:
- Environmental Microbiology
- Bioremediation
- Plant-Bacterial Interactions
Background:
- Previous studies identified a plant-bacterium pair for rhizoremediation of naphthalene.
- Pseudomonas putida PCL1444 was selected for efficient root colonization of grass cv. Barmultra and naphthalene degradation.
Purpose of the Study:
- To analyze Barmultra root exudate composition.
- To investigate the growth rate of P. putida PCL1444 on exudate components.
- To determine the expression of naphthalene degradation genes in response to exudates.
Main Methods:
- High-performance liquid chromatography (HPLC) for root exudate analysis.
- Growth rate assays of P. putida PCL1444 on individual exudate components.
- Analysis of naphthalene degradation gene expression using Tn5luxAB mutants.
Main Results:
- Glucose, fructose, succinic acid, and citric acid were identified as major root exudates.
- Naphthalene degradation gene expression was highest on glucose and succinic acid.
- Salicylic acid, an intermediate, significantly induced both upper and lower naphthalene degradation pathways.
Conclusions:
- Efficient rhizoremediation by the Barmultra-P. putida PCL1444 pair correlates with high utilization of major exudate components.
- High transcription of naphthalene catabolic genes on these components is crucial for remediation success.
- The applied colonization enrichment procedure likely resulted in efficient root colonization and naphthalene degradation.