title: COPPER AMINE OXIDASE1 (CuAO1) of Arabidopsis thaliana contributes to abscisic acid- and polyamine-induced nitric oxide biosynthesis and abscisic acid signal transduction.
abstract: Polyamines (PA), polyamine oxidases, copper amine oxidases, and nitric oxide (NO) play important roles in physiology and stress responses in plants. NO biosynthesis as a result of catabolism of PA by polyamine oxidases and copper amine oxidases may explain in part PA-mediated responses. Involvement of a copper amine oxidase gene, COPPER AMINE OXIDASE1 (CuAO1), of Arabidopsis was tested for its role in stress responses using the knockouts cuao1-1 and cuao1-2. PA-induced and ABA-induced NO production investigated by fluorometry and fluorescence microscopy showed that the cuao1-1 and cuao1-2 are impaired in NO production, suggesting a function of CuAO1 in PA and ABA-mediated NO production. Furthermore, we found a PA-dependent increase in protein S-nitrosylation. The addition of PA and ABA also resulted in H(2)O(2) increases. cuao1-1 and cuao1-2 showed less sensitivity to exogenous ABA supplementation during germination, seedling establishment, and root growth inhibition as compared to wild-type. In response to ABA treatment, expression levels of the stress-responsive genes RD29A and ADH1 were significantly lower in the knockouts. These observations characterize cuao1-1 and cuao1-2 as ABA-insensitive mutants. Taken together, our findings extend the ABA signal transduction network to include CuAO1 as one potential contributor to enhanced NO production by ABA.
authors.affiliation: Leibniz Universität Hannover, Institute of Floriculture and Wood Science, Section of Applied Molecular Physiology, Herrenhäuser Strasse 2, D-30419 Hannover, Germany.
authors.forename: Rinukshi
authors.initials: R
authors.lastname: Wimalasekera
authors.forename: Corina
authors.initials: C
authors.lastname: Villar
authors.forename: Tahmina
authors.initials: T
authors.lastname: Begum
authors.forename: Günther F E
authors.initials: GF
authors.lastname: Scherer
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D006631:Amine Oxidase (Copper-Containing) / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D009569:Nitric Oxide / Q000096:biosynthesis*; D011073:Polyamines / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D011073:Polyamines; D009569:Nitric Oxide; D000040:Abscisic Acid; D006631:Amine Oxidase (Copper-Containing)