Bonjour,
Nous proposons un sujet de thèse intitulé : « Événements climatiques extrêmes comme facteurs de stress aigus pour les micro-organismes des sols agricoles : Exploration des processus éco-évolutifs décryptés par analyses du microbiote sur cellules uniques ». La thèse se déroulera à l’UMR 6553 CNRS Université de Rennes ECOBIO et sera dirigée par Philippe Vandenkoornhuyse et Stéphane Derocles.
Résumé du sujet de thèse :
Climate change–induced heat and drought act as strong filters on soil microbiomes, selecting for stress-tolerant taxa and reshaping functions like those involved in carbon and nitrogen cycling.
Plant microbiota is largely recruited from soil and play a major role in plant nutrition, stress tolerance, and productivity. Consequently, any changes in soil microbial communities may affect plant microbiota and have important consequences on agroecosystems Effects of drought and heat on soil microbial communities is well-documented. However, the population selection processes are still unknown. In this PhD project, we aim to address this gap by testing the following 3 hypotheses:
1) Exposure to heat and drought is expected to reduce soil and plant microbial richness and diversity while increasing the relative abundance of generalist microorganisms
2) Microbial responses to stress are hypothesized to be highly heterogeneous, even among genetically identical cells. This heterogeneity would be driven by differences in gene expression, growth rate, metabolic state, and local interactions.
3) Selective advantage for this heterogeneity would rely on division of labor, subpopulations with slower growth or altered gene expression and microbe–microbe interactions as well as cross-feeding.
To test these hypotheses, the project will combine sampling (soil and plant) from a long-term field experiment to single-cell DNA and RNA sequencing approaches. These high-resolution approaches will be used to resolve cellular heterogeneity, rare taxa, and functional dynamics. By removing the locks from bulk methods, single-cell sequencing represents a promising new challenge to explore eco-evolutionary processes in microbial communities.
Une description complète du sujet de thèse se trouve sur le site de l’école doctorale :
https://amethis.doctorat.org/amethis-client/prd/consulter/offre/3087
Pour candidater, merci d’envoyer CV et lettre de motivation avant le 14 mai à Philippe Vandenkoornhuyse et Stéphane Derocles : philippe.vandenkoornhuyse@univ-rennes.fr stephane.derocles@univ-rennes.fr
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