The apoplastic copper amine oxidase AtCuAOβ plays a role in stomatal closure induced by wounding, jasmonate or Microbe Associated Molecular Patterns (MAMPS)

Copper amine oxidases (CuAOs) convert polyamines to aminoaldehydes producing ammonia and hydrogen peroxide and are involved in key development processes and stress responses. It is known that AtCuAOβ (At4g14940), encoding an apoplastic CuAO, is expressed in root protoxylem and in guard cells. In this study we have investigated AtCuAOβ role in stomatal responses to wounding, Methyl-Jasmonate (MeJA) and bacterial elicitor treatments. AtCuAOβ is induced by leaf or root wounding, consistent with previous data showing AtCuAOβ induction of expression upon treatment with the wound-signal, MeJA. Moreover, AtCuAOβ gene expression is induced by MAMPS such as the 22-amino acid peptide flg22, present in bacterial flagellin, and the 18-amino acid peptide elf18 present in bacterial elongation factor EFTu. Wounding/MeJA/elicitor-induced stomatal closure was analyzed in atcuaoβ T-DNA insertional mutant lines. Under physiological conditions no differences between WT and mutants were observed, while mutants were not responsive to the different treatments inducing stomatal closure. These data suggest that AtCuAOβ could be involved in stomatal responses to pathogen infection and mechanical damage.