[Conjugative transfer of plasmid DNA between bacteria in soil]

Conjugative transfer of plasmid RP4 between populations of azospirilla and between Escherichia coli and Azospirillum brasilense in nonsterile soil has been investigated. The process of genetic exchange was realized at the early stages of interpopulational interactions, further on the process intensity was obviously rather low. Population dynamics of azospirilla transconjugates in soil depends on the presence or the absence of additional food substrate.