title: Does NO play a role in cytokinin signal transduction?
abstract: We tested the hypothesis that nitric oxide (NO) plays an important role in cytokinin signaling. Inhibitors of NO-synthase (NOS), L-NMMA and L-NAME, inhibited the expression of the GUS gene controlled by the cytokinin-responsive ARR5 promoter. However, the inactive analogues D-NMMA and D-NAME had a similar inhibitory activity. NO donors alone did not induce GUS activity and the NO scavenger cPTIO did not prevent the induction of the ARR5 promoter by cytokinin. Northern blot analysis of the P(ARR5)::GUS transgene and the host ARR5 gene revealed that cytokinin-induced transcript accumulation was not altered by NMMA-treatment, indicating that NMMA acts post-transcriptionally. Together the data show that NO has no direct role in eliciting the primary cytokinin response in plants.
authors.affiliation: Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia. gar@ippras.ru <gar@ippras.ru>
authors.forename: Georgy A
authors.initials: GA
authors.lastname: Romanov
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Lomin
authors.forename: Natalia Yu
authors.initials: NY
authors.lastname: Rakova
authors.forename: Alexander
authors.initials: A
authors.lastname: Heyl
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmülling
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D003583:Cytokinins / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter / Q000187:drug effects; D005966:Glucuronidase / Q000235:genetics; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D003583:Cytokinins; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D005966:Glucuronidase; D019331:NG-Nitroarginine Methyl Ester