Transcriptomic perspective on extracellular ATP signaling: a few curious trifles.

Extracellular ATP is perceived by the purinoceptor P2K1, leading to induction of defense response in plants. Previously, we described the transcriptomic response to extracellular ATP in wild-type Arabidopsis seedlings and mutants of classical defense hormone signaling pathways (Jewell et al., 2019, Plant Physiol. 179: 1144-58), in which extracellular ATP was found to induce defense-related genes independently and also along with other defense signaling pathways. In the present study, we provide further analysis and discussion of the data that we neglected to describe in the previous transcriptomics report. Briefly, we describe transcriptomic differences between a knockout mutant () and wild-type seedlings in the absence of exogenous ATP as well as an analysis of genes more responsive to extracellular ATP in a overexpression line. Finally, we describe an exaggerated response to extracellular ATP in the mutant and suggest testable explanations of this phenomenon.