r/K selection of GC content in prokaryotes

Area of Science:

• Microbiology
• Genomics
• Evolutionary Biology

Background:

• Prokaryotic guanine/cytosine (GC) content exhibits species-specific variation (16%-77%).
• The evolutionary drivers for this GC content diversity are debated.
• GC content influences prokaryotic traits and ecological strategies.

Purpose of the Study:

• To analyze correlations between GC content and prokaryotic phenotypic/genotypic data.
• To integrate GC content diversity into the r/K selection theory.
• To understand the ecological implications of GC content variation.

Main Methods:

• Analysis of GC content in thousands of prokaryotic genomes.
• Correlation analysis with phenotypic and genotypic data.
• Integration with r/K selection theory, considering phenotypic plasticity.

Main Results:

• High GC content prokaryotes (r-strategists) exhibit lower amino acid metabolic costs, utilize flagella and bacillus morphology for unstable environments, and act as generalists.
• Low GC content prokaryotes (K-strategists) specialize in stable environments, use outer cell membranes and endospores for homeostasis and nutrient deprivation, and achieve higher nutrient-to-biomass yield.
• GC-rich codons correlate with cheaper amino acids, reducing proteome cost in high GC prokaryotes.

Conclusions:

• Prokaryotic GC content diversity is linked to ecological r/K selection strategies.
• GC content variation reflects adaptations to different environmental stabilities and resource utilization.
• The observed patterns support GC content as a molecular consequence of ecological pressures.