Characterizing a stable five-species microbial community for use in experimental evolution and ecology.

Model microbial communities are regularly used to test ecological and evolutionary theory as they are easy to manipulate and have fast generation times, allowing for large-scale, high-throughput experiments. A key assumption for most model microbial communities is that they stably coexist, but this is rarely tested experimentally. Here we report the (dis)assembly of a five-species microbial community from a metacommunity of soil microbes that can be used for future experiments.

Why do mobile genetic elements transfer DNA of their hosts?

The prokaryote world is replete with mobile genetic elements (MGEs) - self-replicating entities that can move within and between their hosts. Many MGEs not only transfer their own DNA to new hosts but also transfer host DNA located elsewhere on the chromosome in the process. This could potentially lead to indirect benefits to the host when the resulting increase in chromosomal variation results in more efficient natural selection.

Parallel ecological and evolutionary responses to selection in a natural bacterial community.

Evolution can occur over ecological timescales, suggesting a potentially important role for rapid evolution in shaping community trait distributions. However, evidence of concordant eco-evolutionary dynamics often comes from in vitro studies of highly simplified communities, and measures of ecological and evolutionary dynamics are rarely directly comparable. Here, we quantified how ecological species sorting and rapid evolution simultaneously shape community trait distributions by tracking within- and between-species changes in a key trait in a complex bacterial community.

Disturbances can facilitate prior invasions more than subsequent invasions in microbial communities.

Invasions are commonly found to benefit from disturbance events. However, the importance of the relative timing of the invasion and disturbance for invader success and impact on community composition remains uncertain. Here, we experimentally test this by invading a five-species bacterial community on eight separate occasions-four before a disturbance and four after.