Gene transfer in bacteria from soils contaminated with heavy metals

Transfer of metal resistance plasmids into two pseudomonad recipients, Pseudomonas aureofaciens and Ps. putida, from soil bacteria donor populations, was investigated in agricultural soil contaminated predominantly with Zn and Cu. The putative donor and recipient numbers on selective agar were not affected by the concentration of metals in the soils, nor were the number of transconjugants. However, there were differences in transfer frequencies of Hg and Cu resistance from the different soil samples. This is the first time that transfer of Cu resistance has been observed from native bacteria present in agricultural soils.