Research teams

Senescence, Autophagy, Nutrient Recycling and Nitrogen Use Efficiency

SATURNE 7 members

The SATURNE team brings together experts in molecular physiology who are interested in the recycling of nutrients in plants.
They study the metabolism of nitrogen at different stages of the leaf senescence and during plant aging, the genetic bases regulating the recycling and mobilization of nutrients, the mechanisms of autophagy and proteolysis and the consequences for grain filling. The aim of their work is to provide fundamental knowledge facilitating the comparison of the mechanisms of aging and autophagy in plant and animal. They provide useful data for the development of diagnostic and for improving nitrogen use efficiency.

Biological Questions
Four major research questions are central in the SATURNE team's topics:
-What are the molecular actors and fundamental mechanisms put in place during the aging of plant organs to ensure the management of nutritional recycling?
-How do these actors allow plants to adapt to environmental changes and manage climate hazards?
- What is the contribution of these factors to the efficiency of nitrogen utilization and the nutritional quality of the grain?
-How to manipulate these recycling mechanisms in plants of agronomic interest in order to bring agriculture practices more respectful of the environment?

Models, tools and methods
SATURNE team is studying the metabolism and physiological mechanisms of nitrogen remobilization at the whole plant level (fluxomic), at the scale of the organ (enzymology, metabolome) and the cell (genes, vesicular traffic). SATURNE is particularly interested in the role of proteases and autophagy in the degradation of mobilizable nitrogen resources, in the role of enzymes such as glutamine synthetases in the reassimilation of the nitrogen released by the catabolic processes, and in the role of nitrogen transporters in the flow of nutrient to the seeds.

For this, the nutrient fluxes and the progression of the leaf senescence are evaluated in kinetics throughout the development of the plant and under different environments. The modeling of these fluxes makes it possible to establish a diagnosis of the nitrogen remobilization efficiency and to better understand the environmental genotype (GxE) interactions.
The work is carried out on different genotypes of Arabidopsis (mutants and natural accessions) and cultivated plants (barley and wheat).
Leaf senescence scores are evaluated by imaging, chlorophyll measurements, and molecular markers.
Omics tools allow a fine analysis of the foliar metabolism.
Nitrogen fluxes are measured by the use of isotopes such as 15N thanks to the dedicated devices for which the team is in charge.

Societal and economical impacts
The work of the SATURNE team responds to the following societal and economic questions:
(i) the reduction of the use of fertilizers in agriculture,
(ii) the quality of the products harvested specially regarding protein contents,
(iii) the nitrogen use efficiency,
(iv) the long term conservation of postharvest products,
(v) the adaptation of plants to the hazards of climate change.
Senescence, Autophagy, Nutrient Recycling and Nitrogen Use Efficiency


Céline Masclaux-Daubresse