Glutamate triggers long-distance, calcium-based plant defence signalling
Science 14 Sep 2018:
Vol. 361, Issue 6407, pp. 1112-1115
DOI: 10.1126/science.aat7744
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Rapid, long-distance signalling in plants
A plant injured on one leaf by a nibbling insect can alert its other leaves to begin anticipatory defence responses. Working in the model plant Arabidopsis, Toyota et al. show that this systemic signal begins with the release of glutamate, which is perceived by glutamate receptor–like ion channels (see the Perspective by Muday and Brown-Harding). The ion channels then set off a cascade of changes in calcium ion concentration that propagate through the phloem vasculature and through intercellular channels called plasmodesmata. This glutamate-based long-distance signalling is rapid: Within minutes, an undamaged leaf can respond to the fate of a distant leaf.
Abstract
Animals require rapid, long-range molecular signalling networks to integrate sensing and response throughout their bodies. The amino acid glutamate acts as an excitation neurotransmitter in the vertebrate central nervous system, facilitating long-range information exchange via activation of glutamate receptor channels. Similarly, plants sense local signals, such as herbivore attack, and transmit this information throughout the plant body to rapidly activate defence responses in undamaged parts. Here we show that glutamate is a wound signal in plants. Ion channels of the GLUTAMATE RECEPTOR–LIKE family act as sensors that convert this signal into an increase in intracellular calcium ion concentration that propagates to distant organs, where defence responses are then induced.
