Damage can be signalled by extracellular ATP (eATP) using plasma membrane (PM) receptors to effect cytosolic free calcium ion ([Ca2+]cyt) increase as a second messenger. The downstream PM Ca2+channels remain enigmatic. Here, the Extracellular ATP‐induced changes in single epidermal cell PM voltage and conductance were measured electrophysiologically, changes in root [Ca2+]cytwere measured with aequorin, and root transcriptional changes were determined by quantitative real‐time PCR. Two Extracellular ATP‐induced transient depolarization of Arabidopsis root elongation zone epidermal PM voltage was Ca2+dependent, requiring CNGC2 but not CNGC4 (its channel co‐subunit in immunity signalling). Activation of PM Ca2+influx currents also required CNGC2. The eATP‐induced [Ca2+]cytincrease and transcriptional response in CYCLIC NUCLEOTIDE‐GATED CHANNEL2 is required for eATP‐induced epidermal Ca2+influx, causing depolarization leading to [Ca2+]cytincrease and damage‐related transcriptional response.
Extracellular ATP (eATP) is known to act as a danger signal in both plants and animals. In plants, eATP is recognized by the plasma membrane (PM)‐localized receptor P2K1 (LecRK‐I.9). Among the first measurable responses to eATP addition is a rapid rise in cytoplasmic free calcium levels ([Ca2+]cyt), which requires P2K1. However, the specific transporter/channel proteins that mediate this rise in [Ca2+]cytare unknown. Through a forward genetic screen, we identified an Arabidopsis ethylmethanesulfonate (EMS) mutant impaired in the [Ca2+]cytresponse to eATP. Positional cloning revealed that the mutation resided in the
- Award ID(s):
- 1826803
- PAR ID:
- 10445267
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 109
- Issue:
- 6
- ISSN:
- 0960-7412
- Page Range / eLocation ID:
- p. 1386-1396
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Summary Arabidopsis thaliana Ca2+channel subunit CYCLIC NUCLEOTIDE‐GATED CHANNEL2 (CNGC2) was identified as a critical component linking eATP receptors to downstream [Ca2+]cytsignalling in roots.cngc2 loss‐of‐function mutants were used:cngc2‐3 anddefence not death1 (which expresses cytosolic aequorin).cngc2 roots were significantly impaired. -
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