Plasmid-Encoded Traits Vary across Environments

Area of Science:

• Microbial genetics and evolution
• Environmental microbiology
• Bioinformatics

Background:

• Plasmids are mobile genetic elements crucial for bacterial adaptation.
• Current research often overlooks plasmid-borne traits beyond antibiotic resistance.
• Understanding plasmid trait diversity across environments is vital for predicting microbial community adaptation.

Purpose of the Study:

• To analyze the properties and accessory traits of a large plasmid dataset.
• To investigate how plasmid-encoded traits vary across different environmental contexts.
• To assess the role of host taxonomy and environmental selection on plasmid trait composition.

Main Methods:

• Analysis of 9,725 unique plasmid sequences from a public database.
• Characterization of plasmid accessory traits, including Clusters of Orthologous Genes (COG) functions, resistance genes, and carbon/nitrogen metabolism genes.
• Comparison of trait distributions across seven distinct environmental types (human, animal, wastewater, plant, soil, marine, freshwater).

Main Results:

• Antibiotic resistance genes comprised less than 1% of plasmid-encoded genetic information.
• Plasmid trait composition varied significantly across different environments and bacterial host taxonomies.
• Environmental selection, independent of host taxonomy, influences plasmid trait composition.
• Approximately half of the analyzed plasmids were potentially mobilizable.

Conclusions:

• Plasmids encode a wide array of adaptive traits beyond antibiotic resistance.
• Plasmid trait diversity is shaped by both host association and environmental pressures.
• Plasmids serve as significant reservoirs for mobilizable adaptive traits in microbial communities.
• Investigating plasmid-borne traits is essential for understanding microbial adaptation to environmental changes.