Phages carry interbacterial weapons encoded by biosynthetic gene clusters.

Area of Science:

• Microbiology
• Genomics
• Biochemistry

Background:

• Bacteria produce specialized metabolites via biosynthetic gene clusters (BGCs) crucial for ecological interactions and natural product discovery.
• Understanding BGCs offers insights into microbial competition and horizontal gene transfer.
• Phage-encoded BGCs (pBGCs) are underexplored, prompting investigation into their structure, function, and origin.

Purpose of the Study:

• To investigate the prevalence, structure, and function of phage-encoded BGCs (pBGCs).
• To challenge the relationship between phage origin and BGC characteristics.
• To understand the ecological role and evolutionary implications of pBGCs.

Main Methods:

• Bioinformatic analysis of pBGCs across diverse phage genomes.
• Experimental validation using Bacillus subtilis to demonstrate BGC transfer and fitness advantage.
• Genetic and genomic comparisons to identify associations between pBGCs and phage host range.

Main Results:

• pBGCs are rare, predominantly found in temperate phages infecting bacterial hosts.
• The majority of pBGCs encode bacteriocins, conferring a competitive fitness advantage to the host bacterium.
• A strong association exists between pBGC type and phage host specificity.
• Horizontal transfer of functional BGCs via temperate phages was experimentally confirmed.

Conclusions:

• Temperate phages carrying BGCs, particularly for bacteriocins, offer evolutionary benefits to their bacterial hosts.
• Lysogenic conversion by phages encoding BGCs shapes bacterial interactions and facilitates metabolite transfer.
• This highlights a mutualistic relationship between certain bacteria and temperate phages, impacting microbial ecology and natural product biosynthesis.