text: Different kinds of stimuli result in different responses within the Arabidopsis plant. A wound or damage to the plant causes a wound-activated surface potential (WASP) changes that serve as an alert message to undamaged tissues. This wound response results in a plasma membrane depolarization, H+ and Ca efflux and K+ influx, causing an action potential. This action potential causes Ca cytosolic concentration to increase, therefore sending calcium into the phloem, where the signaling is spread, and as it arrives to systemic tissues. Because of the various stimuli perceived by the plant, abiotic and biotic stress results in different amplitudes, durations, frequencies and localizations of Ca concentrations. These “calcium signatures” encode information about the nature of the stimulus and different signatures are sensed by different sensor proteins. With herbivory being an abiotic stressor, Ca is sensed by the regulatory ubiquitin protein calmodulin, which phosphorylates JAV1. In turn, it ubiquitinates JAV1 so it no longer inhibits the biosynthesis of JA, giving a rapid increase of the JA hormone. This increase signals the defense system to begin transcribing JA inducible defense genes against herbivory. Alert messages are generated and propagated throughout the plant to undamaged tissues through WASPs, Ca, and hormonal signals, such as JA.