The Evolution and Ecology of Bacterial Warfare

• Published in: Current biology Vol. 29; no. 11; pp. R521 - R537
• Main Authors: Granato, Elisa T., Meiller-Legrand, Thomas A., Foster, Kevin R.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 03.06.2019
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2019.04.024

Bacteria have evolved a wide range of mechanisms to harm and kill their competitors, including chemical, mechanical and biological weapons. Here we review the incredible diversity of bacterial weapon systems, which comprise antibiotics, toxic proteins, mechanical weapons that stab and pierce, viruses, and more. The evolution of bacterial weapons is shaped by many factors, including cell density and nutrient abundance, and how strains are arranged in space. Bacteria also employ a diverse range of combat behaviours, including pre-emptive attacks, suicidal attacks, and reciprocation (tit-for-tat). However, why bacteria carry so many weapons, and why they are so often used, remains poorly understood. By comparison with animals, we argue that the way that bacteria live — often in dense and genetically diverse communities — is likely to be key to their aggression as it encourages them to dig in and fight alongside their clonemates. The intensity of bacterial aggression is such that it can strongly affect communities, via complex coevolutionary and eco-evolutionary dynamics, which influence species over space and time. Bacterial warfare is a fascinating topic for ecology and evolution, as well as one of increasing relevance. Understanding how bacteria win wars is important for the goal of manipulating the human microbiome and other important microbial systems. Bacteria have evolved a wide range of mechanisms to harm and kill their competitors, but why they do so remains poorly understood. Granato et al. explore the diversity and evolution of bacterial weapons and argue that the way bacteria live is key to their aggression, which drives complex coevolutionary dynamics over space and time.