Plant-associated bacteria and their role in the success or failure of metal phytoextraction projects: first observations of a field-related experiment


  • Funding Information This research was funded by the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen), PhD grant for J.J., and by the Fund for Scientific Research Flanders (FWO-Vlaanderen), PhD grant for S.C. and post doc grant for N. We. and N. Wi. This work has been financially supported by the UHasselt Methusalem project 08M03VGRJ and by the European Commission under the Seventh Framwork Programme for Research (FP7-KBBE-266124, GREENLAND).

For correspondence. E-mail; Tel. (+32) 11 26 83 16; Fax (+32) 11 26 83 01.


Phytoextraction has been reported as an economically and ecologically sound alternative for the remediation of metal-contaminated soils. Willow is a metal phytoextractor of interest because it allows to combine a gradual contaminant removal with production of biomass that can be valorized in different ways. In this work two willow clones growing on a metal-contaminated site were selected: ‘Belgisch Rood’ (BR) with a moderate metal extraction capacity and ‘Tora’ (TO) with a twice as high metal accumulation. All cultivable bacteria associated with both willow clones were isolated and identified using 16SrDNA ARDRA analysis followed by 16SrDNA sequencing. Further all isolated bacteria were investigated for characteristics that might promote plant growth (production of siderophores, organic acids and indol acetic acid) and for their metal resistance. The genotypic and phenotypic characterization of the isolated bacteria showed that the TO endophytic bacterial population is more diverse and contains a higher percentage of metal-resistant plant growth promoting bacteria than the endophytic population associated with BR. We hypothesize that the difference in the metal accumulation capacity between BR and TO clones might be at least partly related to differences in characteristics of their associated bacterial population.