Interspecies Bacterial Comjugation by Plasmids from Marine Environments Visualized by gfp Expression
1998; Oxford University Press; Volume: 15; Issue: 4 Linguagem: Inglês
10.1093/oxfordjournals.molbev.a025935
ISSN1537-1719
AutoresCecilia Dahlberg, Mats Bergström, Mette Findal Andreasen, Bjarke Bak Christensen, Søren Molin, Malte Hermansson,
Tópico(s)Genomics and Phylogenetic Studies
ResumoHorizontal transmission of DNA between different species may have played an important role in evolutionary history. Gene transfer encoded by bacterial plasmids has occurred between distantly related bacterial species; it may have occurred between species of different kingdoms. We have developed a system to detect conjugal plasmid transfer in situ based on the expression of the green fluorescent protein (GFP). Plasmids were tagged with the gfp gene under the control of a lac promoter. These plasmids were placed in a Pseudomonas putida strain carrying a chromosomal lac repressor. In conjugation mixtures, the donor strain remained nonfluorescent, but any newly formed transconjugant cell fluoresced. Unlike other assays for conjugation, this assay is sensitive enough to detect the formation of a single transconjugant a short time after it occurs. We tested for the transfer of three plasmids that were originally exogenously isolated from marine bacterial communities. Eleven of the 19 different eubacterial recipients formed transconjugants, including a species only distantly related to the donor, Planctomyces maris. The results imply that interspecies gene transfer mediated by conjugation is common in natural environments, and may explain why similar DNA sequences can be found among distantly related bacterial species.
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