Sequence characterization and comparative analysis of three plasmids isolated from environmental Vibrio spp

Area of Science:

• Microbiology
• Genetics
• Genomics

Background:

• Horizontal gene transfer via mobile genetic elements (plasmids, phages) significantly impacts Vibrio species' genome diversification.
• This diversification affects their physiology, pathogenicity, and ecological roles.

Purpose of the Study:

• To analyze the genetic diversity of three plasmids isolated from Vibrio species found in salt marsh sediment.
• To investigate potential genetic exchange mechanisms between Vibrio plasmids, phages, and chromosomes.

Main Methods:

• Sequence analysis of three Vibrio plasmids (p0908, p23023, p09022) to determine size, protein-coding sequences, and G+C content.
• Phylogenetic analysis using host 16S rRNA and rpoA sequences to identify host-plasmid relationships.
• Comparative analysis of predicted proteins against databases to identify similarities with known phage, plasmid, and chromosomal proteins.

Main Results:

• The analyzed plasmids (p0908: 81.4 kb, p23023: 52.5 kb, p09022: 31.0 kb) exhibited significant diversity in size and predicted protein content.
• Phylogenetic analysis linked p23023 and p09022 to Vibrio mediterranei and Vibrio campbellii, respectively, while p0908's host clustered with Vibrio fluvialis and Vibrio furnissii.
• Numerous predicted proteins showed homology to known phage and plasmid proteins, with some exhibiting similarity to chromosomal proteins (e.g., RecA, NdpA, UvrD).
• Plasmid p0908 displayed substantial genetic similarity to enterobacteria phage P1.

Conclusions:

• The study demonstrates the remarkable diversity of plasmids within Vibrio species from marine environments.
• Evidence suggests significant genetic exchange occurs between Vibrio plasmids, phages, and their host chromosomes.
• These findings highlight the role of mobile genetic elements in shaping the genomic landscape and evolution of Vibrio populations.