Ca2+ Imaging in Plants Using Genetically Encoded Yellow Cameleon Ca2+ Indicators

Abstract

Temporally and spatially defined changes in cellular calcium (Ca2+) concentration represent stimulus-specific signals and regulate a myriad of biological processes. The development of ratiometric Ca2+ reporter proteins like Yellow Cameleons (YCs) has greatly advanced our ability to analyze Ca2+ dynamics in vivo with unprecedented spatial and temporal resolution. In plants, the application of these Ca2+ reporter proteins has been pioneered for the investigation of Ca2+ dynamics in guard cells, and recently their use has been extended to other single-cell models like growing pollen tubes and root hairs. However, in plants, the use of YC reporter proteins has largely remained restricted to the investigation of cytoplasmic alterations of Ca2+ concentrations. Here, we provide an introduction to current methods for imaging Ca2+ dynamics with increasing sophistication.