Extracellular ATP plays an important role in systemic wound response activation

Area of Science:

• Plant biology
• Plant signaling
• Molecular plant pathology

Background:

• Mechanical wounding in plants activates long-distance signaling pathways.
• Systemic signals include electric signals, calcium, hydraulic, and reactive oxygen species (ROS) waves.
• Glutamate (Glu) signaling via GLU-LIKE RECEPTORs (GLRs) is a known wound response pathway.

Purpose of the Study:

• To investigate the role of extracellular ATP (eATP) in triggering systemic wound responses (SWRs) in Arabidopsis.
• To determine if eATP activates the systemic ROS wave and identify the involved receptors.

Main Methods:

• Quantification of eATP levels in wounded Arabidopsis leaves.
• Application of eATP to unwounded leaves to assess ROS wave induction.
• Analysis of ROS wave activation in P2K receptor mutants (p2k1-3, p2k2, p2k1-3p2k2) during wounding and eATP application.
• Measurement of systemic wound response (SWR) transcript expression in P2K mutants.

Main Results:

• Wounding induces nanomolar levels of eATP in Arabidopsis, sufficient to trigger the systemic ROS wave.
• The P2K receptor is essential for eATP- and wounding-induced ROS wave activation.
• eATP application alone can trigger the ROS wave.
• SWR transcript expression is suppressed in P2K mutants during wounding.
• The effects of Glu and eATP on ROS wave activation are not additive, suggesting a shared pathway.

Conclusions:

• Extracellular ATP (eATP), sensed by PURINORECEPTOR 2 KINASE (P2K), is a key signal triggering systemic wound responses (SWRs) in plants.
• eATP acts via the ROS wave pathway, potentially in parallel or convergence with glutamate signaling.
• This finding expands the known signaling mechanisms involved in plant defense against mechanical stress.