Recombinant plasmid mobilization between E. coli strains in seven sterile microcosms

Area of Science:

• Microbiology
• Environmental Science
• Molecular Biology

Background:

• Genetically engineered microorganisms (GEMOs) may be accidentally released into various environments.
• Understanding the transfer of recombinant DNA is crucial for assessing the ecological impact of GEMOs.
• The pBR derivative plasmid used lacks essential transfer functions (oriT+, tra-, mob-).

Purpose of the Study:

• To investigate the mobilization and transfer of a pBR derivative recombinant plasmid between E. coli K12 strains.
• To assess plasmid transfer in diverse sterile microcosms representing potential environments for GEMOs.
• To determine the influence of environmental conditions on recombinant DNA mobilization.

Main Methods:

• Utilized seven sterile microcosms: biofilm, soil, seawater, freshwater, wastewater, mouse gut, and mussel gut.
• Introduced E. coli K12 strains carrying a pBR derivative recombinant plasmid lacking transfer functions.
• Monitored survival of GEMOs and quantified plasmid transfer rates across different environments.

Main Results:

• GEMOs exhibited similar survival rates to host strains across all tested microcosms.
• Recombinant DNA mobilization was detected in the mouse gut, sterile soil, and biofilm.
• Plasmid transfer rates were significantly influenced by the specific environmental conditions within each microcosm.

Conclusions:

• Mobilization of recombinant plasmids can occur in specific environments even without complete transfer functions.
• Environmental conditions play a key role in regulating the mobility and potential spread of engineered DNA.
• Findings highlight the need for environmental risk assessments considering plasmid transfer dynamics in GEMO applications.