Extracellular ATP signaling regulates systemic calcium signaling in the response of <i>Arabidopsis</i> seedlings to local wounding

The response of plants to local environmental stimuli can be activated in the tissues or organs that are directly challenged, as well as systemically in the remote and unstressed tissues or organs. Extracellular ATP (eATP) is known to play key roles in regulating many physiological processes in plants. Here, we demonstrated that local wounding at leaf or root of Arabidopsis thaliana seedling triggers a transient systemic increase in eATP levels, preceding the systemic elevation of [Ca2+]cyt levels in remote, un-wounded tissues. By using GCaMP3-p2k1 single-mutant, GCaMP3-p2k2 single-mutant, and GCaMP3-p2k1p2k2 double-mutant plants, it was found that local wounding-induced increases of [Ca2+]cyt levels at systemic tissues were weakened by P2Ks (eATP receptors) mutation. These results indicate that eATP/P2Ks are involved in regulating local and systemic enhancement of [Ca2+]cyt levels in response to local wounding.