Distinct role of AtCuAOβ- and RBOHD-driven HO production in wound-induced local and systemic leaf-to-leaf and root-to-leaf stomatal closure.

Polyamines (PAs) are ubiquitous low-molecular-weight aliphatic compounds present in all living organisms and essential for cell growth and differentiation. The developmentally regulated and stress-induced copper amine oxidases (CuAOs) oxidize PAs to aminoaldehydes producing hydrogen peroxide (HO) and ammonia. The CuAOβ (AtCuAOβ) was previously reported to be involved in stomatal closure and early root protoxylem differentiation induced by the wound-signal MeJA apoplastic HO production, suggesting a role of this enzyme in water balance, by modulating xylem-dependent water supply and stomata-dependent water loss under stress conditions.

A New Player in Jasmonate-Mediated Stomatal Closure: The Copper Amine Oxidase β.

Plant defence responses to adverse environmental conditions include different stress signalling, allowing plant acclimation and survival. Among these responses one of the most common, immediate, and effective is the modulation of the stomatal aperture, which integrates different transduction pathways involving hydrogen peroxide (HO), calcium (Ca), nitric oxide (NO), phytohormones and other signalling components. The () encodes an apoplastic CuAO expressed in guard cells and root protoxylem tissues which oxidizes polyamines to aminoaldehydes with the production of HO and ammonia.