Persistence of DNA in Natural Soils: Adsorption to Particulate Material Provides Protection Against Nucleolytic Degradation

Abstract

The release of genetically engineered organisms to the environment bears the risk of a transfer of recombinant DNA to organisms in natural habitats. In particular, the presence of in vitro recombined nucleotide sequences in bacteria of the environment could lead to their increased fitness or other new phenotypes resulting in disturbance of the microbial community. Among bacteria, genes can be horizontally transmitted by conjugation, transduction, and transformation. In our laboratory, the various aspects of genetic transformation of soil bacteria is studied which is the cell-to-cell transfer of naked DNA. In bacterial habitats, such as soil and sediment, DNA-degrading enzymes produced by bacteria are ubiquitously present. This raises the question of whether DNA may persist long enough to interact with transformable soil bacteria and to be finally taken up by them. Here we present data showing that DNA can persist in soil for several days if the DNA adsorbs to soil particulate material.