Avis de Soutenance

Habilitation à Diriger des Recherches

Vendredi 24 mai 2024

à 09h30 Amphi 206

Campus INRA/SupAgro Montpellier

Multi-faceted and integrated approaches to unravel water flows and water status in plant roots, under stationary and transient conditions

Yann Boursiac

Institut des Sciences des Plantes de Montpellier

Mme INGRAM Gwyneth, Directeur de recherche, RDP, ENS Lyon, Lyon France
Mme ROBERT Stéphanie, Professor, Umea Plant Science Center, Umea, Suède
Mr CHAUMONT François, Full professor, Université Catholique de Louvain, Louvain La Neuve, Belgique
Mr SIMMONNEAU Thierry, Directeur de recherche, LEPSE, INRAE, Montpellier France
Mr LACOMBE Benoît, Directeur de recherche, IPSiM, CNRS, Montpellier France
Mr GODIN Christophe, Directeur de recherche, RDP, ENS Lyon, Lyon France
Mr GALAUD Jean-Philippe, Professeur, LRSV, INRAE, Castanet-Tolosan France

Research in plant biology, even at the most fundamental level, needs to address today important issues for the future. These include meeting the growing nutritional needs of the world’s population in a context of limited resources, or evaluating wild plants adaptation to climate change. This is particularly true for water, the quality and quantity of which will increasingly be challenged. Understanding how water circulates within plants and how plant water status is shaped by the environment are two of the cornerstones of addressing this issue.

To study water flows under stationary conditions, I have developed projects in functional and integrative biology, in which we have been able to test how “usual suspects” are involved in the water transport capacity of a root, notably apoplastic diffusion barriers such as the Casparian strips and suberin. This work has been enriched by modeling approaches, at the scales of tissues and organ, which have enabled us to gain a better understanding of how root structures (architecture, vessels, anatomy) influence water transport and integrate into a root hydraulic architecture.

My projects will evolve towards a more dynamic vision of water flows and plant water status. Transient conditions appear in contexts such as water deficit treatment, and I am interested in the variations in the physico-chemical environment around the root (components of the water potential), and how they are transduced into a biological response. recent work shows that plant cells respond transcriptionally to two distinct parameters during water stress: variations in turgor and osmotic pressure. Further study of two candidate genes quantitatively regulated by these parameters reveals the involvement of complex mechanisms, including mRNA degradation pathways, in these responses.