Journal of Soils and Sediments

, Volume 13, Issue 1, pp 176–188

Potential of willow and its genetically engineered associated bacteria to remediate mixed Cd and toluene contamination

  • Nele Weyens
  • Kerim Schellingen
  • Bram Beckers
  • Jolien Janssen
  • Reinhart Ceulemans
  • Daniel van der Lelie
  • Safiyh Taghavi
  • Robert Carleer
  • Jaco Vangronsveld
SOILS, SEC 5 • SOIL AND LANDSCAPE ECOLOGY • RESEARCH ARTICLE

DOI: 10.1007/s11368-012-0582-1

Cite this article as:
Weyens, N., Schellingen, K., Beckers, B. et al. J Soils Sediments (2013) 13: 176. doi:10.1007/s11368-012-0582-1

Abstract

Purpose

The purpose of this study was to investigate if bacteria with beneficial properties that were isolated from willow growing on a metal-contaminated site can be further equipped with genes coding for a specific degradation pathway to finally obtain transconjugants that can be inoculated in willow to improve phytoremediation efficiency of mixed contaminations.

Materials and methods

Cultivable rhizosphere bacteria and root endophytes were isolated from willow (cv. Tora) growing on a metal-contaminated soil. All isolated strains were tested for their metal resistance and potential to promote plant growth. The two most promising strains were selected and were equipped with the pTOM plasmid coding for toluene degradation. Both transconjugants were inoculated separately and combined in willow cuttings exposed to mixed Cd–toluene contamination, and their effect on phytotoxicity, Cd uptake, and toluene evapotranspiration was evaluated.

Results and discussion

Many of the isolated strains tested positive for the production of siderophores, organic acids, and indole acetic acid (IAA) and showed increased Cd resistance. The Cd-resistant, siderophore-producing rhizosphere strain Burkholderia sp. HU001 and the Cd-resistant root endophyte Pseudomonas sp. HU002, able to produce siderophores, organic acids, and IAA, were selected as receptors for conjugation with the toluene-degrading Burkholderia vietnamiensis BU61 as a donor of the pTOM-TCE plasmid. Although inoculation with the individual transconjugant strains had no effect on plant growth and negatively affected Cd uptake, their combined inoculation resulted in an increased shoot biomass upon Cd–toluene exposure did not affect Cd uptake and strongly reduced evapotranspiration of toluene to the atmosphere.

Conclusions

In this study, inoculation of willow with a consortium of plant-associated bacteria equipped with the appropriate characteristics resulted in an improved phytoremediation of a mixed Cd–toluene contamination: the degradation of toluene was improved leading to a decreased toxicity and evapotranspiration, while Cd uptake and translocation were not affected.

Keywords

Cadmium Co contamination Plant-associated bacteria Salix Toluene Willow 

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Nele Weyens
    • 1
  • Kerim Schellingen
    • 1
  • Bram Beckers
    • 1
  • Jolien Janssen
    • 1
  • Reinhart Ceulemans
    • 2
  • Daniel van der Lelie
    • 3
  • Safiyh Taghavi
    • 3
  • Robert Carleer
    • 1
  • Jaco Vangronsveld
    • 1
  1. 1.Centre for Environmental SciencesHasselt UniversityDiepenbeekBelgium
  2. 2.Biology Department, Campus Drie EikenUniversity of AntwerpWilrijkBelgium
  3. 3.Research Triangle Institute (RTI) InternationalResearch Triangle ParkUSA

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