title: Salicylic acid activates nitric oxide synthesis in Arabidopsis.
abstract: The relationship between nitric oxide (NO) and salicylic acid (SA) was investigated in Arabidopsis thaliana. Here it is shown that SA is able to induce NO synthesis in a dose-dependent manner in Arabidopsis. NO production was detected by confocal microscopic analysis and spectrofluorometric assay in plant roots and cultured cells. To identify the metabolic pathways involved in SA-induced NO synthesis, genetic and pharmacological approaches were adopted. The analysis of the nia1,nia2 mutant showed that nitrate reductase activity was not required for SA-induced NO production. Experiments performed in the presence of a nitric oxide synthase (NOS) inhibitor suggested the involvement of NOS-like enzyme activity in this metabolic pathway. Moreover, the production of NO by SA treatment of Atnos1 mutant plants was strongly reduced compared with wild-type plants. Components of the SA signalling pathway giving rise to NO production were identified, and both calcium and casein kinase 2 (CK2) were demonstrated to be involved. Taken together, these results suggest that SA induces NO production at least in part through the activity of a NOS-like enzyme and that calcium and CK2 activity are essential components of the signalling cascade.
authors.affiliation: Dipartimento di Biologia, Università Degli Studi di Padova, Via U. Bassi 58/B, I-35131 Padova, Italy. mzottini@bio.unipd.it
authors.forename: Michela
authors.initials: M
authors.lastname: Zottini
authors.forename: Alex
authors.initials: A
authors.lastname: Costa
authors.forename: Roberto
authors.initials: R
authors.lastname: De Michele
authors.forename: Maria
authors.initials: M
authors.lastname: Ruzzene
authors.forename: Francesco
authors.initials: F
authors.lastname: Carimi
authors.forename: Fiorella
authors.initials: F
authors.lastname: Lo Schiavo
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism*; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D020156:Salicylic Acid / Q000494:pharmacology*; D013053:Spectrophotometry; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D020156:Salicylic Acid