title: Hydrogen peroxide generated by copper amine oxidase is involved in abscisic acid-induced stomatal closure in Vicia faba.
abstract: H(2)O(2) is an essential signal in absicic acid (ABA)-induced stomatal closure. It can be synthesized by several enzymes in plants. In this study, the roles of copper amine oxidase (CuAO) in H(2)O(2) production and stomatal closure were investigated. Exogenous ABA stimulated apoplast CuAO activity, increased H(2)O(2) production and [Ca(2+)](cyt) levels in Vicia faba guard cells, and induced stomatal closure. These processes were impaired by CuAO inhibitor(s). In the metabolized products of CuAO, only H(2)O(2) could induce stomatal closure. By the analysis of enzyme kinetics and polyamine contents in leaves, putrescine was regarded as a substrate of CuAO. Putrescine showed similar effects with ABA on the regulation of H(2)O(2) production, [Ca(2+)](cyt) levels, as well as stomatal closure. The results suggest that CuAO in V. faba guard cells is an essential enzymatic source for H(2)O(2) production in ABA-induced stomatal closure via the degradation of putrescine. Calcium messenger is an important intermediate in this process.
authors.affiliation: College of Life Sciences, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: An
authors.forename: Wen
authors.initials: W
authors.lastname: Jing
authors.forename: Youliang
authors.initials: Y
authors.lastname: Liu
authors.forename: Wenhua
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020013:Calcium Signaling; D005021:Ethylamines / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism*; D019255:NADPH Oxidases / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology; D054046:Plant Stomata / Q000187:drug effects* / Q000502:physiology*; D011073:Polyamines / Q000494:pharmacology; D031307:Vicia faba / Q000187:drug effects* / Q000201:enzymology*
chemical_list: D005021:Ethylamines; D006146:Guanidines; D010937:Plant Growth Regulators; D011073:Polyamines; C004504:2-bromoethylamine; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D006631:Amine Oxidase (Copper-Containing); D019255:NADPH Oxidases; C004479:pimagedine