Expression of pH-sensitive green fluorescent protein in Arabidopsis thaliana

This is the first report on using green fluorescent protein (GFP) as a pH r eporter in plants. Proton fluxes and pH regulation play important roles in plant cellular activity and therefore, it would be extremely helpful to hav e a plant gene reporter system for rapid, non-invasive visualization of int racellular pH changes. In order to develop such a system, we constructed th ree vectors for transient and stable transformation of plant cells with a p H-sensitive derivative of green fluorescent protein. Using these vectors, t ransgenic Arabidopsis thaliana and tobacco plants were produced. Here the a pplication of pH-sensitive GFP technology in plants is described and, for t he first time, the visualization of pH gradients between different developm ental compartments in intact whole-root tissues of A. thaliana is reported. The utility of pH-sensitive GFP in revealing rapid, environmentally induce d changes in cytoplasmic pH in roots is also demonstrated.