Context
Despite the impact of yeasts on terrestrial ecosystems, including humans, their diversity remains poorly characterized and fundamental aspects of their ecology are not well understood. Recent work suggests the existence of mutualistic relationships between yeasts and pollinators, but these studies remain divided into either ‘molecular-cellular’ or ‘ecological-evolutionary’ approaches. The aim of this project is to fill this gap through an original and interdisciplinary project, at the interface between molecular genetics and functional ecology, in order to characterize the adaptation of yeasts to nectar and bee products, as well as the role of yeasts in plant-bee interactions (a tripartite system).
The proposed PhD is part of an interdisciplinary project (POMBEE, MITI CNRS) that aims to characterise the nature of bee-yeast interactions, and to identify the impact of yeasts on floral choices and bee health, thus tackling an important issue in the context of the global changes facing biodiversity. The PhD will focus on the chemical and functional aspects of this tripartite biotic interaction, by asking original research questions and using a variety of methodological approaches.
Description of the PhD project
The doctoral student will have two main objectives: (i) characterize the role of yeasts in the floral choices of bees, and (ii) study their impact on bee health, particularly in the context of global changes. For the first objective, the recruited person will carry out analyses of volatile organic compounds (VOCs) emitted by yeasts in conditions that impact bee floral choices, as well as electrophysiological recordings and behavioural tests in olfactometers. Altogether, we expect these results to establish whether yeasts emit particular volatile signals and whether these signals are detected and used by pollinators to guide them in their floral choices. For the second objective, the recruited person will be in charge of biological tests under controlled conditions on two bee models (experimental ecology). Different parameters related to the reproduction and immunity of bees will be measured in order to determine the impact of different species and strains of yeast on the reproductive success and health of bees. These bio-assays will be carried out under optimal breeding conditions, but also under conditions of exposure to various environmental stress factors (ozone episodes mimicking atmospheric pollution, heat waves), alone or in combination to establish synergistic effects. These different trials will help determine whether yeasts can make pollinators more resilient to global planetary changes. We will further examine whether yeasts induce a self-medication behaviour in bees, by establishing whether the preference of pollinators for yeasts improves their resilience when they are subjected to environmental stress factors.
Supervision
The PhD will be co-supervised by Dom Helmlinger (CRBM) and Maryse Vanderplanck (CEFE), who work in two different CNRS institutes, located on the same campus, and bring complementary expertise in yeast genetics and functional ecology, respectively. The person recruited will work in close collaboration with a doctoral student currently in her first year of thesis within the CRBM team, and whose research focuses on the adaptation of yeasts to nectar and bee products. The recruited person will thus participate in the genetic characterization of the production of VOCs by yeasts and in the phenotypic tests of yeasts isolated from bees and colonies.
This PhD represents a unique opportunity to work with a wide range of techniques and to develop many interdisciplinary skills (ecology, physiology, chemistry, microbiology, genetics) within the CEFE and CRBM teams.
Application
Send an e-mail with a covering letter and CV to the following addresses: dominique.helmlinger@crbm.cnrs.fr ; maryse.vanderplanck@cefe.cnrs.fr
Please also apply online via the following link: https://emploi.cnrs.fr/Gestion/Offre/Default.aspx?Ref=UMR5237-HIEPHA-006
Please include the contact details of two referees, preferably course supervisors.
Start: 1st of January 2024, for a period of three years.