Sex as a driving force for microbial community evolution in forest soil
PIs : Pierre Leblond et Cyril Bontemps (UMR 1128 Dynamique des génomes et adaptation microbienne — DYNAMIC)
___________________________________________________________________
Context — The predominant role of horizontal gene transfer in bacterial evolution is now well established, but the open question remains its prevalence in the ecosystem and particularly its contribution to adaptation of the bacterial community to environmental changes. We will address this question by focusing our approach to the Streptomyces genus, bacteria of forest soils involved in microbial interactions as well as in biogeochemical recycling.
Objectives — We aim at estimating gene fluxes in the rhizosphere (i) by measuring genetic recombination within the soil population, and (ii) by identifying recent transfer events in the modern genomes.
Approach — In an innovative approach, we will exploit a collection of environmental isolates realized from soil ‘micro-niches’ (scale of soil grain, i.e. 8 to 20 mm3) in order to maximize the probability of interactions and co-adaptation of bacterial community to the same biotic and abiotic conditions. Then, the isolated Streptomyces strains will be submitted to a diversity analysis at different depths (MSLA, repPCR) followed by a recombination analysis. In parallel, transferred genes will be identified by compared genomics from whole genome sequences of a sample of strains/species.
Finally, genome-based analyses will be completed by phenotypic traits (microbial interactions, antibiotic resistance and production…) in order to understand the contribution of gene fluxes to bacterial adaptation and to the maintenance of diversity within a bacterial population.
Expected results and impacts — Beside fundamental insight into the dynamics of forest soil ecosystem, biotechnological outcome is also expected by the identification of new genes involved in new drug synthesis or new degradative enzymes.
