Séminaire IBIP
Les séminaires ont lieu sur le Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)

Jeudi 28 mars 2013
Salle 104 (Château) à 14h

From root hair elongation to feedback regulation: ethylene in Arabidopsis

Guilhem Desbrosses
Université Montpellier 2, Laboratory of Mediterranean and Tropical Symbiosis

In their environment, plant root rhizosphere is home for many different genus of soil bacteria. They are commonly known as rhizobacteria. It is becoming clear that some of these rhizobacteria are able to affect plant root function and architecture. One of the most spectacular examples is rhizobium that interact with legumes and eventually trigger the formation of a new root organ: the nitrogen fixing nodule. At a different biological scale, there is another example illustrating how some rhizobacteria do affect root hair development and possibly function. In Arabidopsis, several rhizobacteria are able to elongate root hair five to six times more than in the control condition, when they are present in the rhizosphere. Maybe these bacterial strains produce something that affect/interfere with the plant hormonal pathway controlling root hair elongation such as auxin and/or ethylene. In this presentation, I will investigate the mechanism by which rhizobacteria do promote root hair elongation in the model plant Arabidopsis thaliana. I will focus on the implication of the plant ethylene pathway. I will conclude that surprisingly, the ethylene pathway appears only to play a regulatory role into that response. In agreement with that, inoculated-plants produce less ethylene than control plants. While conducting the work, I stepped on the feedback regulation of ethylene biosynthesis, a mechanism that is not well described. Based on genetics, transcript analysis and ethylene measurements, I will provide a revised description on that mechanism. In the conclusion, I will question whether the presence of that mechanism could explain our observations on inoculated plants. Would that mechanism be a target by rhizobacteria during their interaction with Arabidopsis, with all plants?


Contact : Sabine Zimmermann

Contacts IBIP :
Sabine Zimmermann
Philippe Nacry
Christine Granier
Chantal Baracco