The host as an ecosystem: a conceptual framework to study symbiotic interactions

Natacha Kremer

Laboratoire de Biométrie et Biologie Evolutive, CNRS,

Université Claude Bernard, Lyon

natacha.kremer@univ-lyon1.fr

Link to onsite registration: TBA

Link to online seminar: TBA

Symbiotic interactions, which range from parasitism to mutualism, are ubiquitous in nature. They involve a wide variety of symbionts, which may be more or less intimately associated with their host. The balance between the cost associated with the presence of the symbiont (i.e., use of nutrients and cellular machinery, virulence) and its benefit (i.e., nutritional complementation, immune protection against pathogens) defines the position of the symbiotic association along the continuum.

Symbiotic interactions are classically studied in a binary manner, describing the impact of the symbiont on the life history traits of the host, and conversely the influence of the host on the population dynamics of the symbiont. The study of binary associations also makes it possible to characterize in detail the mechanisms involved in the molecular dialogue between the partners. But more recently, studies have begun to take into account not only the diversity of host and microbe genotypes, but also the multitude of interactions within a host. This ecosystemic vision implies studying each symbiont as a potential modifier of the host extended phenotype, but also considering the role of symbiotic interactions in the expression of the extended phenotype, and the influence of the environment on the system.

My research work falls within this conceptual framework. Indeed, I question the host as an ecosystem, using various symbiotic associations and approaches. In this talk, I will present parts of this integrative questioning, such as the rules of assembly between ecosystem partners, the mechanisms of maintenance and control of symbiotic partners, the impact of interactions between multiple symbionts on the host phenotype, or the resilience of symbiotic associations in response to stressors and their role on adaptation.

Watch previous seminars on our YouTube channel: https://www.youtube.com/channel/UCrX4IsZ8WIFcDa0ZmC7rcQg