Involvement of Arabidopsis thaliana Copper Amine Oxidase β in maturation of root protoxylem precursors induced by leaf wounding

Root architecture and anatomy are strictly related to crop productivity especially under environmental stress. In particular, metaxylem plasticity enhances water uptake and improves plant performance to protect yield under water stress. Xylem vessels maturation depends on coordinated events of cell wall lignification and developmental PCD, which both are triggered by a developmental- and/or stress-driven oxidative burst. Copper amine oxidases (CuAOs) oxidize polyamines to aminoaldehydes, producing H2O2 and ammonia. In this regard, the Arabidopsis AtCuAOβ is expressed in guard cells and root xylem tissues, in which it plays a role in the MeJA-induced early protoxylem differentiation. In this study, the involvement of AtCuAOβ in maturation of root protoxylem precursors induced by leaf wounding was investigated by reverse genetic approaches. An early root protoxylem differentiation was observed in leaf-cut WT plants, while atcuaoβ insertional mutants were unresponsive in the same conditions, suggesting that the cell-wall localized AtCuAOβ plays a role in root protoxylem phenotypic plasticity triggered by systemic leaf-to-root signaling pathways after leaf wounding.