IMPORTANT LEGAL NOTICE - The information on this site is subject to a disclaimer and a copyright notice
Banner Research
English
 
  European Commission   > Research > GMO
 
EC-sponsored Research on Safety of Genetically Modified Organisms - A Review of Results
imageIntroductionimage Research areasimage Toolsimage Project 05
Graphic element Graphic element Graphic element

image
 
 button Introduction
image
 button Foreword
image
 button Research areas
imageimageimage Plants
imageimageimage Plant  microbes
imageimageimage Biocontrol
imageimageimage Food
imageimageimage Bioremediation
imageimageimage Tools
imageimageimage Fish
imageimageimage Vaccines
image
 button Index of participants
image
image Monitored environment release of genomically tagged phylloplane and rhizosphere bacteria

Background and objectives

There is an increasing interest in the use of bacteria as vectors for the delivery of plant protection genes to combat insect pests and control pathogens. Before they can be developed and applied in the field, an understanding of the ecology of the phytosphere and surrounding environment is required. As potential vectors will be genetically modified to contain desired traits, studies need to be undertaken to allow predictions of the likely environmental impact on releasing GMOs.

The perceived risks associated with the release of GMOs into the natural environment include concerns that the inoculum may out-compete or perturb the target microbial community and that genetic exchange occurs resulting in the loss or mobilisation of the introduced gene.


Approach and methodology

We isolated common Gram negative bacteria indigenous to the phytosphere of sugar beet (Pseudomonas fluorescens SBW25) and selected Gram positive bacteria with insecticidal activity (Bacillus thuringiensis). We developed methods to generate genetically stable genomically marked bacteria and protocols to monitor the release of tagged bacteria onto plant surfaces. Modelling was used to assess the spread, survival and persistence of the released bacteria. The potential for heterologous gene transfer between members of the natural bacterial population was assessed.


Main findings and outcome

P. fluorescens SBW25 was site specifically marked in a defined, functionally mapped chromosomal location with selectable (Kmr, Tcr) and screenable (Xy1E) genes. B. thuringiensis isolates were manipulated to contain traceable plasmid or chromosomal markers (Mer, Gus, Xy1E). P. fluorescens recombinants, are metabolically indistinguishable from the wild-type, genetically stable, able to colonise plants following seed inoculation and can be passively transmitted by insects. Of 400 bacterial isolates analysed 83 contained plasmids and two were able to self transfer. This study led to a better understanding of microbial succession and gene transfer in the phytosphere relevant to risk assessment following the release of GMOs.


Conclusions

Candidate bacteria were selected and genetically marked for monitored release. Methods were developed for the electroporation of environmental isolates. This study developed a reliable plant experimental model and demonstrated the potential role of insects in GMO dispersal. Naturally occurring tra+ plasmids were isolated from the phylloplane bacterial community.


Major publications

Bailey M.J. & Purdy K.J., “Tracking genetically modified bacteria in the environment”.
Laboratory Practice,
39, 1990, pp. 57-58.

Bailey M.J., Kobayashi N., Lilley A.K., Powell B.J. & Thompson I.P., “Assessment of the potential for gene transfer in the phytosphere of sugar beet”, in Gauthier M.J. (ed.), Gene Transfers and Environment, Springer-Verlag, Berlin, 1992, pp. 143-148.

Powell B.J., Purdy K.J., Thompson I.P. & Bailey M.J., “Demonstration of tra+ plasmid activity in bacteria indigenous to the phyllosphere of sugar beet; gene transfer to a genetically modified pseudomonad”.
FEMS Microbiology – Ecology.,
12, 1993, pp. 195-206.

Kobayashi N & Bailey M.J., “Plasmids isolated from the sugar beet phyllosphere show little or no homology to molecular probes currently available for plasmid typing”.
Microbiology, 140, 1994, pp. 289-295.

Bailey M.J., Kobayashi N., Lilley A.K., Powell B.J. & Thompson I.P., “Potential for gene transfer in the phytosphere: isolation and characterisation of naturally occurring plasmids”, in Bazin M.J. & Lynch J.M. (eds.), Environmental gene release, Chapman Hall, London, 1994, pp. 77-98.
image imageimage image
imageResearch project
 

Contract number
BAP-0141/0369

Period
January 1989 – December 1990

Coordinator
M.J. Bailey
Natural Environment Research Council (NERC)
Oxford (UK)

 
image


Partner


M. van Montagu
Rijksuniversiteit Gent (BE)

 
 
Previous project  | Tools contents | Next project | Top