PhD thesis: Genomic and morphologial characterization of a planktonic symbiosis (M/F)

Organisation/Company CNRS Department Laboratoire de physiologie cellulaire et végétale Research Field Biological sciences Researcher Profile First Stage Researcher (R1) Application Deadline 22 Aug 2026 - 00:00 (UTC) Country France Type of Contract Temporary Job Status Full-time Hours Per Week 35 Offer Starting Date 1 Nov 2026 Is the job funded through the EU Research Framework Programme? Not funded by a EU programme Is the Job related to staff position within a Research Infrastructure? No

Offer Description

The PhD is funded through a "CNRS International" grant from the Mission pour les Initiatives Transverses et Interdisciplinaires (MITI). The project will take place within the Photosymbiosis team (photosymbiosis.com) at the Laboratoire de Physiologie Cellulaire et Végétale (UMR 5168 – CNRS – CEA – Univ. Grenoble Alpes – INRAe), based at CEA Grenoble, under the co-supervision of Prof. Patrick Keeling (University of British Columbia, Vancouver). Alongside the two host laboratories, interactions and collaborations will involve the imaging platforms of Grenoble and EMBL, as well as the Tara Oceans consortium and the FRA GOSEE.

This PhD project focuses on the study of symbioses between marine planktonic hosts (Radiolaria and Dinoflagellates) and cyanobacteria, combining innovative single-cell genomics and imaging approaches. The first objective is to characterize the diversity of host-cyanobiont associations through single-cell genomics in different oceanic regions and seasons. This approach will be complemented by fluorescence and electron microscopy in 3D to finely characterize the physical integration of symbionts within their hosts. The second objective is to study the metabolic connection between host and symbiont using stable isotopes (13C and 15N) coupled with NanoSIMS imaging (Nanoscale Secondary Ion Mass Spectrometry). Finally, the project will also aim to analyze the genomes of cyanobionts from isolated cells, cross-referencing them with existing Tara omics data. In collaboration with Samuel Chaffron (INS2I and FRA GOSEE), modelling analyses will be undertaken to better understand the metabolism of cyanobionts. Overall, this multidisciplinary PhD project will shed new light on the nature of an enigmatic marine symbiosis in the plankton.

Expected skills and knowledge:Training in marine biology and/or oceanographyKnowledge and interest in cellular interactions: mutualistic symbiosis or parasitismKnowledge and expertise in electron microscopy and/or genomic analysis (genome analysis, molecular sequencing)Expertise in microalgae culture and physiology will be appreciatedAbility to work independently in an interdisciplinary and international environment (fluent English), and to interact within a young and dynamic research group