# Prokaryotic defense systems: Diversity and evolutionary adaptation

## TL;DR

This paper reviews how prokaryotes have evolved diverse defense systems against viruses, highlighting their complexity and potential for biotechnology.

## Contribution

The paper provides a comprehensive overview of prokaryotic defense systems and their evolutionary dynamics.

## Key findings

- Prokaryotic defense systems include surface barriers, innate responses, and adaptive defenses.
- The co-evolution of RNA and protein components contributes to defense system diversity.
- Understanding these systems can inform biotechnology and immune system evolution.

## Abstract

Bacteriophages and archaeal viruses are the most abundant biological entities on Earth. Through a long‐standing co‐evolutionary arms race, they have driven the emergence of a diverse repertoire of prokaryotic defense systems. This review summarizes these systems, highlighting their diverse antiviral mechanisms across distinct stages of viral infection, from surface barriers and inducible innate responses to specific adaptive defenses, and the intricate interplay between these defense strategies. By examining host–virus counter defense dynamics, the trade‐off between survival benefit and adaptive cost, the co‐evolution of RNA and protein components, and the comparison with eukaryotic immune systems, we underscore the intrinsic complexity and evolutionary plasticity of prokaryotic antiviral immunity. A deeper understanding of these processes and mechanisms will not only shed light on the origins and evolution of the immune system but also provide valuable opportunities for the development of biotechnological tools.