The seminars take place on the Montpellier Institut Agro/INRAE Campus of La Gaillarde (2, place P. Viala Montpellier)

Thursday, June 06 at 2:00 p.m. – Amphi 208 (Coeur d’Ecole)

Prof. José M. Pardo

Instituto de Bioquímica Vegetal y Fotosíntesis CSIC-Universidad de Sevilla ESPAGNE

SOS3/CBL3, a multitalented protein at the interface between salinity tolerance and flowering

Extremes in environmental conditions are major drivers of natural selection for plants. In unfavorable environments, the transition to flowering is adjusted to maximize the production of dormant structures (seeds) that can survive prolonged adverse episodes and eventually reinitiate a life cycle when conditions improve. Water and nutrient deprivation can quickly compromise survival and generally induce earlier flowering, whereas soil salinity reduces growth and delays flowering. Results will be presented showing that the protein SALT OVERLY SENSITIVE3/CALCINEURIN B-LIKE4 (SOS3/CBL4), a signaling intermediary in the plant response to salinity, results in the selective stabilization of the flowering time regulator GIGANTEA inside the nucleus under salt stress, while degradation of GIGANTEA in the cytosol releases the protein kinase SOS2 to achieve salt tolerance. Moreover, SOS3 acts as a molecular switch governing major sodium fluxes by favoring the recruitment of the Na+/H+ antiporter SOS1 to the plasma membrane and activation by SOS2, while commanding degradation of the channel-like HKT1;1 protein that mediates sodium unloading off the xylem. When sodicity stress exceeds a set point, SOS3 switches the balance from sodium retention in the root toward export to the shoot

Contact : benoit.lacombe@cnrs.fr