Habilitation to do Research Supervision (HDR)

Thursday, April 10, 2025 at 2:00 p.m.
Campus INRAE-SupAgro, Montpellier, Amphi 208

François Barbier
Institute for Plant Sciences of Montpellier (IPSiM)

Role of nutrient signalling in the control of shoot architecture

Jury members:
• Sylvie Dinant (IJPB, Versailles)
• Pierre-Marc Delaux (LRSV, Toulouse)
• Christine Granier (AGAP, Montpellier)
• Sandrine Ruffel (IPSiM, Montpellier)
• Patrick Laufs (IJPB, Versailles)

Abstract :
My research focuses on the developmental processes that govern shoot architecture in response to the nutritional environment. Specifically, I investigate the signaling mechanisms by which sugars and nitrate regulate axillary bud outgrowth and shoot branching. During my PhD and postdoctoral research, I showed that sugars act as signals controlling bud outgrowth across multiple species. My work provided physiological and genetic evidence that these signaling effects are mediated by distinct pathways involving the enzyme-receptor HEXOKINASE1 and the sugar signal trehalose 6-phosphate, and identified key transcription factors, such as bZIP11, that mediate the influence of sugar starvation on shoot branching. Through various collaborations, my research further revealed that sugars promote shoot branching by upregulating cytokinin biosynthesis and by antagonizing strigolactone perception via direct targeting of the F-box protein D3/MAX2. My current research aims to build on these findings by understanding how mineral nutrients, particularly nitrogen, control shoot branching. I am also interested in exploring the evolution of interactions between nutrients and hormones, notably using Marchantia as a model species. In this presentation, I will summarize the main findings of my previous research and provide an overview of my current projects.