Date : 15/06/2011

Internship proposal for : Master 1 or Master 2

Laboratory
Laboratoire Joliot-Curie - USR3010
ENS Lyon & CNRS
46, Allee d'Italie
69007 Lyon
Website : http://www.ens-lyon.fr/Joliot-Curie/spip.php?rubrique53
Main discipline : Biophysics
Lab director : Françoise Argoul

Mentor
Prof. Arezki Boudaoud
email : This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
phone : 04 72 72 88 75

Subjects
1.: Morphogenesis
2.: Development
3.: Mechanics

Tools and methodologies
1.: Molecular Biology
2.: Atomic Force Microscope
3.: Confocal Microscopy

Summary of lab's interests

Our team combines biological, physical and computational approaches to Development. We address the emergence of shape, how shape serves as a template for differentiation and how shape feeds back on cell identity. Our model system is the shoot apex of Arabidopsis, which is a major determinant of plant architecture. In addition to standard molecular tools, we are developing cutting-edge methods for live imaging and mechanical characterization.

Summary of project

The emergence of shape in an organism involves changes in its structural elements -- adding new materials and remodeling old materials. In this context, morphogenesis appears as a physical process controlled at the cellular level. Therefore the investigation of morphogenesis must also address the mechanical properties of the structural elements of the organism during its development. How do cells regulate their mechanical properties ? How do these properties guide morphogenesis ? Plants are perfectly suited for these questions, as their shape is mostly imposed by their stiff cell walls and by turgor. The main goal of the project is to establish three-dimensional maps of the mechanical properties of the plant tissues and to validate this map using pharmacological treatments and transgenic constructions. The principle is to use micromechanical manipulations (including Atomic Force Microscopy) and osmotic treatments to deform cells and to infer relative mechanical propertie s by quantifying deformations. Preliminary results obtained in the team indicate the feasibility of this approach and suggest a regional specification of mechanical properties. Wild type plants will be compared to plants with pharmacological treatments affecting cell walls, or to plants where cell wall synthesis or remodeling is locally modified using well-chosen promoters. In a first step, we will perform a comparative study of stem segments, hypocotyls and roots, and address the longstanding question of the relative role of epidermal and internal tissues in growth. More generally, this work will help building a new framework for morphogenesis, linking cellular behavior directly with shape.