Sponging of glutamate at the outer plasma membrane surface reveals roles for glutamate in development.

Plants use electrical and chemical signals for systemic communication. Herbivory, for instance, appears to trigger local apoplasmic glutamate accumulation, systemic electrical signals, and calcium waves that travel to report insect damage to neighboring leaves and initiate defense. To monitor extra- and intracellular glutamate concentrations in plants, we generated Arabidopsis lines expressing genetically encoded fluorescent glutamate sensors.

Interdependence of a mechanosensitive anion channel and glutamate receptors in distal wound signaling.

Glutamate has dual roles in metabolism and signaling; thus, signaling functions must be isolatable and distinct from metabolic fluctuations, as seen in low-glutamate domains at synapses. In plants, wounding triggers electrical and calcium (Ca) signaling, which involve homologs of mammalian glutamate receptors. The hydraulic dispersal and squeeze-cell hypotheses implicate pressure as a key component of systemic signaling.