On a Fitzhugh–Nagumo type model for the pulse-like jasmonate defense response in plants

• Positive feedback in jasmonate signaling leads to bistable signaling.
• Negative feedback to the jasmonate bistable network yields an excitable system.
• The excitable jasmonate system exhibits pulse-like dynamics.

A mechanistic model of the Fitzhugh–Nagumo type is proposed for the pulse-like jasmonate response in plants. The model is composed of a bistable signaling pathway coupled to a negative feedback loop. The bistable signaling pathway describes a recently discovered positive feedback loop involving jasmonate and the MYC2 transcription factor regulating promoter activity during plant defense. The negative feedback loop is assumed to reflect a second jasmonate-dependent signaling pathway that is also used for ethylene signaling. The impact of the negative feedback loop is to destroy the high-level jasmonate fixed-point of the bistable jasmonate/MYC2 module. As a result, the high-level state becomes a ghost attractor and the jasmonate defense response becomes pulse-like.