Coevolution

Bacteria and their viruses coexist and coevolve in nature, but maintaining them together in the lab is challenging. Here, a spatially structured environment allowed prolonged coevolution, with bacteria and phage diversifying into multiple ecotypes, uncovering gene mechanisms affecting phage-bacteria interactions.

In this study, the microbiota of multiple body sites from 101 marine fish species from Southern California were sampled and analysed. The authors compared diversity measures while also establishing a method to estimate microbial biomass. Body site is shown to be the strongest driver of microbial diversity and patterns of phylosymbiosis are observed across the gill, skin and hindgut.

The ecological and evolutionary impacts of disease vary in spatially structured populations. Here, the authors study ~4000 populations of Plantago lanceolata and find that resistance evolution depends on both disease history and population structure, with isolated populations more susceptible to fungal disease.

Here, the authors show that a colonizing bacterial strain evolves in the gut by either generating ecotypes or continuously fixing beneficial mutations. They associate the first mode to metabolic mutations and the second to domestication of bacteriophages that are incorporated into the bacterial genome.