Investigating uptake of recombinant DNA from Roundup Ready soybeans by soil microorganisms

Glyphosate [N-(phosphonomethyl)glycine] prevents the biosynthesis of aromatic amino acids by inhibiting 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), an enzyme present in plants, bacteria and fungi. Roundup ReadyRTM soybean [Glycine max (L.) Merr.] contains a glyphosate-tolerant version of the gene (cp4 epsps). Uptake of the transgenic cp4 epsps gene by the soil bacteria Acinetobacter sp. BD413 and Bradyrhizobium japonicum 532C was investigated in vitro and in planta, respectively. Acinetobacter pRANGER:Delta222 cp4 epsps exposed to between 10 and 1000 ng of CP4 EPSPS DNA showed uptake of the gene via homologous recombination. Increasing amounts of DNA were also correlated with a higher frequency of natural transformation. In planta natural transformation of B. japonicum 532C with the genomic cp4 epsps gene was not detected, indicating either (1) natural transformation of the microorganism was not taking place, (2) natural transformation rates were below detection, or (3) uptake of the gene did not result in an increased tolerance to the herbicide.