Special Seminar - Steven Quistad: Experimental manipulation of Selfish Genetic Elements (SGEs) links genes to microbial community function
- rescheduled: new date on March 22
- Date: Mar 22, 2019
- Time: 11:00 AM - 12:00 PM (Local Time Germany)
- Speaker: Steven Quistad from the École Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI), France
- More information on the speaker can be found here: http://www.stevenquistad.com/
- Location: MPI Plön
- Room: Lecture hall
- Host: Paul Rainey
Abstract:
Microbial
communities underpin earth’s biological and biogeochemical
processes. Selfish Genetic Elements (SGEs) drive the evolution
of microbial communities via the direct transfer of DNA between
host cells. While some SGEs may transfer genes that provide the
host with a selective advantage more often SGE invasion results
in a neutral or negative impact on host fitness. Therefore, the
survival of most SGEs is dependent on their ability to
successfully transfer to a new host cell. Here we set out to
design an experiment that would promote SGE transfer with the
goal of observing SGE eco-evolutionary dynamics and their
subsequent impact on the evolution of microbial communities. Ten
microbial communities were founded from compost and grown in
minimal media supplemented with a piece of cellulose paper
serving as the sole carbon source. Following establishment, the
founding communities were split into two transfer regimes:
Vertical and Horizontal. In the Vertical regime each of the ten
communities were homogenized every two weeks and transferred to
fresh medium with a new piece of cellulose paper. In the
Horizontal regime each transfer involved the founding microbial
community as well as an “SGE-cocktail” sampled from all ten
bottles, thus providing the opportunity for SGEs to move between
Horizontal but not Vertical communities. Using comparative
metagenomics, we provide evidence for large-scale movement of
genetic material between Horizontal communities including
predicted genes involved with ecologically relevant traits such
as iron acquisition, virulence factors, and transcription. As a
general proxy for community function we also measured the
ammonia concentrations during the course of the two-week
incubation period. Surprisingly, we found that the Horizontal
communities had significantly higher ammonia production compared
to their Vertical counterparts. To our knowledge these data
describe for the first time the emergence of a functional impact
of SGEs on a complex microbial community through direct
experimentation.