Environ. Biosafety Res.
Volume 6, Number 1-2, January-June 2007Thematic Issue on Horizontal Gene Transfer
|Page(s)||85 - 89|
|Published online||12 September 2007|
Assessment of transformability of bacteria associated with tomato and potato plants
Wageningen University and Research Centre, Plant Research
International B.V., Wageningen, Droevendaalsesteeg 1, The Netherlands
2 Department of Pharmacy, Faculty of Medicine, University of Tromsø, 9037, Tromsø, Norway
3 University of Groningen, Centre for Ecology and Evolutionary studies, Department of Microbial Ecology, Kerklaan 30, 9751 NN Haren, The Netherlands
Corresponding author: firstname.lastname@example.org
Transformation of plant-associated bacteria by plant DNA has never been demonstrated in agricultural fields. In total 552 bacterial isolates from stems of Ralstonia solanacearum-infected and healthy tomato plants and from stems and leaves of healthy potato plants were tested for natural genetic competence using plasmid pSKTG DNA and homologous DNA extracts. Control strain Acinetobacter baylyi ADP1 was transformable with both DNA extracts. No transformable isolates were observed after treatment with plasmid pSKTG DNA. Two isolates, P34, identified as Pseudomonas trivialis and A19, identified as Pseudomonas fragi, were selected on the basis of the consistently higher Rp-resistant CFU numbers after treatment with DNA from Rp-resistant cells than with that from wild-type cells. P34 showed 2.1-fold and A19 1.5-fold higher Rp-resistant CFU numbers after treatment with DNA from homologous Rp-resistant cells versus that from wild-type cells. It is concluded that bacteria capable of in vitro capture and integration of exogenous DNA into their genomes are relatively rare in culturable bacterial communities associated with tomato and potato plants, or that conditions conducive to transformation were not met in transformation assays.
Key words: transformation / plant-associated bacteria / homologous recombination / bacterial endophytes
© ISBR, EDP Sciences, 2007