The power of ionic movements in plants

Summary The movement of ion‐driven electrogenic events known as plant action potentials in the Venus flytrap Dionaea muscipula has first been recognized in Darwin's time. Besides electrophysiological techniques making use of current‐ and voltage‐recording electrodes, today an ever‐growing spectrum of tools has become available, that report online changes in membrane potential and ion concentration. This represents a big step forward, particularly in comparison to the ‘dark’ times when calcium‐signaling studies could not take advantage of Ca 2+ reporters. Very recently, the first tools from a potpourri of light‐gated ion channels routinely used in neurobiology took the plant signaling field to a new level. This kind of genetically encoded, noninvasive opto‐tools can be activated by light and provide for remote controlling the membrane potential and ionic second messengers such as Ca 2+ and H + . In future studies, such optogenetic tools in combination with the appropriate reporters for ionic and electrical impulses will allow studying membrane‐delimited early steps in plant signal transduction. Moreover, this toolbox will help us tackle the question of how, for example, Ca 2+ and/or electrical signatures are assessed in terms of local and long‐distance information management.