2002 Volume 56 Issue 1 Pages 3-10
A biomarker, gfp gene, was introduced into a strain of Ralstonia solanacearum isolated from tomato to investigate the fate of this strain in soil. Tn5-mutants of the strain SL8 were virulent against tomatoes. The behavior of these gfp-fused mutants was similar to that of the wild type strain both in the culture medium and in soil. In the case of the gfp-fused mutants in which the production of extracellular polysaccharides (EPS) was impaired or absent (EPS-), the fluorescence of GFP was useful to discriminate between the inoculated strains from other indigenous bacteria in soil. In conclusion, the biomarker GFP allowed the count of both wild type strains, one which produced large amounts of EPS and the other PC-type mutants in terms of EPS. Subsequently, the gfp-fused mutants of Ralstonia solanacearum enabled to analyze the factors that induce phenotypic conversion from wild type strains under environmental conditions.
