title: Polyamines induce rapid biosynthesis of nitric oxide (NO) in Arabidopsis thaliana seedlings.
abstract: In this study, we examined the regulation by putrescine, spermidine and spermine of nitric oxide (NO) biosynthesis in Arabidopsis thaliana seedlings. Using a fluorimetric method employing the cell-impermeable NO-binding dye diaminorhodamine-4M (DAR-4M), we observed that the polyamines (PAs) spermidine and spermine greatly increased NO release in the seedlings, whereas arginine and putrescine had little or no effect. Spermine, the most active PA, stimulated NO release with no apparent lag phase. The response was quenched by addition of 2-aminoethyl-2-thiopseudourea (AET), an inhibitor of the animal nitric oxide synthase (NOS) and plant NO biosynthesis, and by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-1-oxy-3-oxide (PTIO), an NO scavenger. By fluorescence microscopy, using the cell-permeable NO-binding dye diaminorhodamine-4M acetoxymethyl ester (DAR-4M AM), we observed that PAs induced NO biosynthesis in specific tissues in Arabidopsis seedlings. Spermine and spermidine increased NO biosynthesis in the elongation zone of the Arabidopsis root tip and in primary leaves, especially in the veins and trichomes, while in cotyledons little or no effect of PAs beyond the endogenous levels of NO-induced fluorescence was observed. We conclude that PAs induce NO biosynthesis in plants.
authors.affiliation: Universität Hannover, Institut für Zierpflanzenbau, AG Molekulare Ertragsphysiologie, Germany.
authors.forename: Ni Ni
authors.initials: NN
authors.lastname: Tun
authors.forename: Claudete
authors.initials: C
authors.lastname: Santa-Catarina
authors.forename: Tahmina
authors.initials: T
authors.lastname: Begum
authors.forename: Vanildo
authors.initials: V
authors.lastname: Silveira
authors.forename: Walter
authors.initials: W
authors.lastname: Handro
authors.forename: Eny Iochevet Segal
authors.initials: EI
authors.lastname: Floh
authors.forename: Günther F E
authors.initials: GF
authors.lastname: Scherer
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000378:metabolism*; D001120:Arginine / Q000494:pharmacology; D003497:Cyclic N-Oxides / Q000494:pharmacology; D005453:Fluorescence; D007093:Imidazoles / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects; D011073:Polyamines / Q000494:pharmacology*; D011700:Putrescine / Q000494:pharmacology; D012235:Rhodamines / Q000494:pharmacology; D036226:Seedlings / Q000187:drug effects* / Q000378:metabolism*; D013096:Spermine / Q000494:pharmacology; D000338:beta-Aminoethyl Isothiourea / Q000494:pharmacology
chemical_list: D003497:Cyclic N-Oxides; D007093:Imidazoles; D011073:Polyamines; D012235:Rhodamines; C508638:diaminorhodamine-4M; D000338:beta-Aminoethyl Isothiourea; C079391:2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; D013096:Spermine; D009569:Nitric Oxide; D001120:Arginine; D011700:Putrescine