pH homeostasis is crucial for all eukaryotic cells. As part of Rhizopolis project founded by Agropolis Fondation, we developed genetically encoded pH sensors to question the role of protons in root functions such as ion uptake and "symbiosis" with micro-organisms found in the soil. We also developed organelle-targeted pH-sensors to study the subcellular distribution of protons and its role in protein transport. Using stable or transient expression systems, we could measure pH in a non-invasive way. Through examples obtained in plant cells, we will illustrate the potential of such sensors combined with live imaging to answer biophysical questions ranging from organelle to organ scale.

Martinière A., Bassil E, Jublanc E, Alcon C, Reguera M, Sentenac H, Blumwald E and Paris N. In vivo intracellular pH measurements in tobacco and Arabidopsis reveal an unexpected pH gradient in the endomembrane system (2013). Plant Cell 25, 4028-4043.

Martinière A, Desbrosses G, Sentenac H and Paris N. Development and properties of genetically encoded pH sensors in plants (2013) Perspectives, Frontiers in Plant Science 4, 523.