41% of Gram-negative bacteria encode a Type Six Secretion System

About 41% of genomes in an average well-sampled Gram-negative genus (with >30 sampled genomes) encode a type six secretion system (T6SS), based on 35,467 representative genomes.

• Why it matters: T6SS is linked to bacterial pathogenesis and evolution, but its prevalence across bacteria is still not well quantified.
• What they did: The authors analyzed 35,467 representative bacterial genomes and estimated T6SS encoding rates per well-sampled Gram-negative genus, then assessed how T6SS presence varies across taxonomic levels.
• The result: T6SS distribution is patchy across all taxonomic levels, consistent with context-dependent selection, repeated evolutionary loss, or greater evolutionary lability, and the dataset plus pipeline enable similar surveys of secretion systems and gene clusters.

AI summary of the abstract · may contain errors · not medical advice · read the paper.