Gene transfer by transduction in the marine environment

Area of Science:

• Microbiology
• Environmental Science
• Molecular Biology

Background:

• Bacteriophages are viruses that infect bacteria and are abundant in marine ecosystems.
• Horizontal gene transfer (HGT) is a significant driver of microbial evolution and adaptation.
• The role of bacteriophages in HGT within marine environments remains incompletely understood.

Purpose of the Study:

• To investigate the potential for bacteriophage-mediated gene transfer in marine environments.
• To establish and utilize transduction systems with marine phage-host isolates.
• To quantify plasmid transduction frequencies in both isolated marine bacteria and natural communities.

Main Methods:

• Plasmid transduction assays using marine bacterial isolates and natural communities as recipients.
• Plasmid pQSR50, containing transposon Tn5 and antibiotic resistance genes, was used for transduction.
• Detection of transductants via gene probes for the neomycin phosphotransferase (nptII) gene and PCR amplification.

Main Results:

• Transduction frequencies in isolated marine bacteria ranged from 1.33 x 10(-7) to 5.13 x 10(-9) transductants/PFU.
• Putative transductants were detected in natural bacterial communities, with frequencies from 1.58 x 10(-8) to 3.7 x 10(-8) transductants/PFU.
• Numerical modeling estimated up to 1.3 x 10(14) transduction events annually in the Tampa Bay Estuary.

Conclusions:

• Transduction is a viable mechanism for horizontal gene transfer in marine environments.
• Phage-mediated gene transfer can occur in both isolated and mixed marine bacterial populations.
• This process may play a crucial role in the adaptation and evolution of marine microbial communities.