Arabidopsis thaliana Cyclic Nucleotide-Gated Channel 19 is involved in root extracellular ATP and Pep1 signalling.

Extracellular ATP (eATP) can function as a damage-associated molecular pattern (DAMP) that signals wounding incurred by microbial ingress and herbivore attacks (Tanaka and Heil 2021; Yuan et al., 2025). Arabidopsis thaliana root and leaf wounding triggers rapid accumulation of eATP (Dark et al., 2011; Myers Jr. et al., 2022). eATP is then sensed by the plasma membrane (PM) co-receptors DORN1/P2K1 (Does Not Respond to Nucleotide1/P2-type purinoeceptor Kinase 1) and P2K2 (Choi et al., 2014; Pham et al., 2020). The perception of eATP leads to downstream signalling cascades involving elevation of cytosolic free calcium ([Ca2+]cyt), reactive oxygen species and nitric oxide plus MAP Kinase activation (Demidchik et al., 2003; Foresi et al., 2007; Chen et al., 2017; Kim et al., 2023). Analyses of eATP-induced transcriptomes point to DORN1/P2K1-dependent regulation of multiple defence-related hormone signalling pathways involving jasmonic acid (JA), ethylene, and salicylic acid (Tripathi et al., 2017; Jewell et al., 2019). Accordingly, loss-of-function DORN1/P2K1 and P2K2 mutants show increased susceptibility to a variety of plant pathogens including fungi (Rhizoctonia solani and Sclerotinia sclerotiorum), oomycetes (Plasmodiophora brassicae, Phytophthora infestans and Phytophthora capsici) and bacteria (Pseudomonas syringae) plus insect herbivores (Pieris rapae, Salix exigua and Spodoptera litura), whilst receptor overexpression lines reduce plant susceptibility (Bouwmeester et al., 2014; Balagué et al., 2017; Chen et al., 2017; Kumar et al., 2020; Jewell et al., 2022; Kundu et al., 2025; Yuan et al., 2025).