Doctorate thesis of Montpellier University

Thursday october 26 2023  at 2 pm, Amphi 208

Physiological and molecular approaches to better understand early events triggered by water deficit in Arabidopsis roots

Doctoral school : GAIA – Biodiversité, Agriculture, Alimentation, Environnement, Terre, Eau
Spéciality : BIDAP – Biologie, Interactions, Diversité Adaptative des Plantes
University : Université Montpellier
Reasearch unit : IPSiM –  Institut for Plant Sciences of Montpellier

Team: Aqua

Jury:

Mme. Marie-Béatrice Bogeat-Triboulot, Chargée de Recherche, Nancy.    Rapporteur
M. Benoît Landrein, Chargé de recherche CNRS, Lyon.   Rapporteur
Mme. Leslie Sieburth, Full professor, University of Utah Salt Lake City.  Examinatrice
M. Thierry Simonneau, Directeur de recherche INRAE, Montpellier.   Examinatrice
M. Yann BOURSIAC, Chargé de recherche INRAE, Montpellier.   Encadrant de thèse

Abstract:

Water availability stands as one of the most important limiting factor influencing crop productivity. Unraveling the mechanisms governing plant perception of water deficit has become crucial for agriculture, particularly in the context of frequent drought events due to climate change. Plant water potential is primarily composed of two biophysical parameters, the turgor potential (P) and the osmotic potential (Π), that will determine water movements in the soil-plant-atmosphere continuum. Here, decline in external Π and P reduction caused by mild water deficit (MWD, where cortical cells in the elongation zone of the primary root maintained turgidity) were considered as input signals, while early changes in gene expression was taken as a readout. To study the whole-genome transcriptional responses to variations in Π and P, water deficit was induced by treatments of the root with various osmolytes: NaCl, sorbitol, polyethylene glycol 8000 and ethylene glycol (EG), into the hydroponic solution. To further explore the regulatory mechanism of gene expression, we observed the effects caused by the transcriptional inhibitor cordycepin and genetic knockouts of components of mRNA decay pathways. Finally, we aimed at developing Π- and P- reporters, for which we used the regulatory elements (promoter and 3’UTR) of Π- and P- correlated genes to drive the expression of reporters.