In vivo measurements of pH changes in planta – University of Copenhagen

In vivo measurements of pH changes in planta

Changes in pH are now widely accepted as a signalling mechanism in cells. In plants, proton pumps in the plasma membrane and tonoplast play a key role in regulation of intracellular pH homeostasis and maintenance of transmembrane proton gradients. Proton transport in response to external stimuli are expected to be finely regulated spatially and temporally. With the ambition to follow such changes live, a new genetically encoded sensor, pHusion, has been developed.

pHusion is especially designed for apoplastic pH measurements. The great potential for analysing pH regulation in a whole-tissue, physiological context was recently published by the immediate alkalinization of the subepidermal apoplast upon external indole-3-acetic acid administration (Gjetting et al. 2012).

We are now exploring the sensor plants with stimuli such as hormones and growth factors to measure the pH response in planta in real time.

Example of nanosencor expression in Arabidopsis leaves: The ration between GFP (green) and RFP (red) emission intensity reflects the relative pH of the different tissues in the leaf (overlay).

Publication:

  • Gjetting SK, Ytting CK, Schulz A, Fuglsang AT (2012) Live imaging of intra- and extracellular pH in plants using pHusion, a novel genetically encoded biosensor. J. Exp. Bot. 63: 3207 - 3218