Youcef HADDAD PhD defense

Organic Chemistry & Interfaces (COrInt) team

Abstract
While the mechanisms involved in desiccation tolerance (DT) remain partially understood, osmolytes capable of forming hydrogen bonds, such as disaccharides, amino acids, and organic acids, appear to play a crucial role. These compounds are also increasingly used in green chemistry as components of natural deep eutectic solvents (NaDES). Here, we present experimental evidence supporting the hypothesis that NaDES could form a third liquid phase within seed tissues, capable of solubilizing and protecting macromolecules during dehydration. After identifying the putative components of NaDES, referred to as DESmolytes, their colocalization and preferential interactions within seed compartments were revealed using mass spectrometry imaging (MSI). Based on these results, NaDES reconstituted in vitro demonstrated the ability to protect proteins against desiccation and thermal stress, as well as to solubilize secondary metabolites from rapeseed seeds. In the future, these findings will need to be validated in other organisms, such as pollen, in order to further confirm the formation of NaDES in living cells.

Jury
Julia Buitink, Research Director, UMR IRHS, Angers / Reviewer
Erwann Durand, Researcher, UMR QUALISUD, Montpellier / Reviewer
Loïc Rajjou, Professor, UMR IJPB, Versailles / Examiner
Sophie Fourmentin, Professor, UR UCEIV, Dunkerque / Examiner
Vincent Carré, Professor, UR LCP-A2MC, Metz / Examiner
Nathalie Nesi, Research Director, UMR IGEPP, Le Rheu / Examiner
Alain Bouchereau, Professor, UMR IGEPP, Le Rheu / PhD Director
Ludovic Paquin, Associate Professor, ISCR, Univ. Rennes / PhD Co-Director

Contacts
Youcef Haddad, youcef.haddad@etudiant.univ-rennes.fr
Ludovic Paquin, ludovic.paquin@univ-rennes.fr