Abstract
The establishment and maintenance of regular patterns of cells is at the core of development biology. Mechanisms of tissue organization are critical not only during embryogenesis, but also in post-embryonic developmental processes such as for example metamorphosis in animals, plasticity of neural networks, shoot and root branching in plants and organ regeneration in both animals and plants. A theoretical framework describing fundamental organizing laws underlying these processes would represent a major conceptual advancement in biology.
Regeneration – the developmental process of re-growth of a lost structure – can be viewed as a powerful model to discover universal mechanisms of tissue organization in multicellular systems.
In this talk, I will argue that plant roots are ideal model systems to study regeneration at its most fundamental level, for both experimental and abstract reasons. I will discuss some recent unexpected results on the role of stem cells in the regeneration of excised root tips in Arabidopsis. I will also present a novel automated setup specifically developed for imaging every few minutes the entire structure of the Arabidopsis root tip at cellular resolution, as it grows for days. I will show how the collected data allows for a quantitative analysis of the cellular dynamics during root growth and regeneration.
Finally, I will discuss how a combination of quantitative phenomenology and computational modelling will help us distinguishing the roles of two potential mechanisms to describe the tissue reorganization occurring during root regeneration: (a) the action of a central organizer, where a well-defined group of cells acts as “instructor” to the rest of the tissue; or (b) the emergent property of a self-organizing system, where the regenerated tissue structure is the result of local interactions among identical (in first approximation) cells.