Description du sujet de thèse

Like animal cells, plant cells perceive and respond to mechanical constraints from their surrounding tissues and external environment. This process, known as mechanotransduction, involves a cascade of intracellular structures, among which the nuclear envelope plays a central role as a relay between mechanical forces and gene expression regulation. Recent findings suggest that such constraints alter not only nuclear morphology but also chromatin organization and transcriptional activity.
The aim of this PhD project is to elucidate the physical and molecular mechanisms by which plant cell nuclei perceive and integrate mechanical stress. Using a combination of cellular and molecular biology, biophysics (microrheology, AFM), high-resolution microscopy, and multi-omics analyses (RNA-seq, ChIP-seq, proteomics), the PhD candidate will investigate nuclear dynamics in response to various mechanical stresses (osmotic, saline, physical compression) at multiple scales (tissue, single cell, isolated nucleus). They will identify the key players in this response (e.g. SUN proteins, CRWN, plamina components, epigenetic markers) and propose an integrative mechanistic model linking mechanical cues, chromatin reorganization, and transcriptional regulation.
This interdisciplinary project lies at the interface between plant biology, biological physics, and functional genomics, and aims to establish a theoretical and experimental framework to better understand plant resilience to environmental changes.

Contexte de travail

For the selected PhD candidate, the thesis will be conducted under a cotutelle agreement between two well-established and complementary laboratories, offering an interdisciplinary training combining plant biology and biophysics. The PhD candidate will successively join both research units:
1) Institute of Molecular Biology of Plants (IBMP – UPR2357, CNRS), Strasbourg : Located in the heart of Strasbourg, the IBMP is a CNRS research unit affiliated with the Institute of Biological Sciences (INSB), under the regional delegation DR10. It comprises approximately 180 staff members (researchers, engineers, technicians, and PhD students) and conducts fundamental research in plant biology, particularly in genomics, cellular signaling, nuclear organization, and stress responses.
The host team, led by Alexandre Berr (CRCN), specializes in nuclear responses to abiotic stress in plants, with strong expertise in epigenomics, cell imaging, and chromatin analysis. The PhD candidate will have access to IBMP's state-of-the-art technological platforms, including confocal microscopy, proteomics, bioinformatics, and genomics (RNA-seq, ChIP-seq). This part of the thesis will be affiliated with Doctoral School 414 “Health and Life Sciences” in Strasbourg, France.
2) Laboratory Matter and Complex Systems (MSC – UMR7057, Université Paris Cité & CNRS), Paris: The MSC is based in Paris and jointly operated by CNRS and Université Paris Cité. It is affiliated with the INSIS/INP Institute and falls under regional delegation DR2. The lab brings together physicists, biologists, and chemists to study complex systems. The team of Prof. Atef Asnacios, a partner in the project, is a pioneer in the development of micro-rheology, microfluidics, and micromechanics approaches applied to plant cells. The PhD candidate will carry out the biophysical part of the thesis in this laboratory, working closely with experts to quantify the mechanical properties of the nucleus and cytoplasm using innovative tools (AFM, micro-wells, GEMs, etc.). This part of the thesis will be affiliated with Doctoral School 564 “Physics in Île-de-France” (PIF).
The candidate will spend approximately 18 months in each laboratory, thus benefiting from dual theoretical and practical training. This cotutelle arrangement will allow the acquisition of complementary skills in two key scientific domains, supported by high-level interdisciplinary supervision.