The nitric oxide production in the moss Physcomitrella patens is mediated by nitrate reductase.
During the last 20 years multiple roles of the nitric oxide gas (•NO) have been uncovered in plant growth, development and many physiological processes. In seed plants the enzymatic synthesis of •NO is mediated by a nitric oxide synthase (NOS)-like activity performed by a still unknown enzyme(s) and nitrate reductase (NR). In green algae the •NO production has been linked only to NR activity, although a NOS gene was reported for Ostreococcus tauri and O. lucimarinus, no other Viridiplantae species has such gene. As there is no information about •NO synthesis neither for non-vascular plants nor for non-seed vascular plants, the interesting question regarding the evolution of the enzymatic •NO production systems during land plant natural history remains open. To address this issue the endogenous •NO production by protonema was demonstrated using Electron Paramagnetic Resonance (EPR). The •NO signal was almost eliminated in plants treated with sodium tungstate, which also reduced the NR activity, demonstrating that in P. patens NR activity is the main source for •NO production. The analysis with confocal laser scanning microscopy (CLSM) confirmed endogenous NO production and showed that •NO signal is accumulated in the cytoplasm of protonema cells. The results presented here show for the first time the •NO production in a non-vascular plant and demonstrate that the NR-dependent enzymatic synthesis of •NO is common for embryophytes and green algae.
Laboratorio de Fisiología y Desarrollo Vegetal, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México.
Rigoberto
R
Medina-Andrés
Departamento de Química Inorgánica y Nuclear, Facultad de Química, Universidad Nacional Autónoma de México, México D.F., México.
Alejandro
A
Solano-Peralta
Departamento de Química Inorgánica y Nuclear, Facultad de Química, Universidad Nacional Autónoma de México, México D.F., México.
Juan Pablo
JP
Saucedo-Vázquez
Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
Selene
S
Napsucialy-Mendivil
Laboratorio Nacional de Microscopia Avanzada, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
Jaime Arturo
JA
Pimentel-Cabrera
Departamento de Química Inorgánica y Nuclear, Facultad de Química, Universidad Nacional Autónoma de México, México D.F., México.
Martha Elena
ME
Sosa-Torres
Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
Joseph G
JG
Dubrovsky
Laboratorio de Fisiología y Desarrollo Vegetal, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México.
Verónica
V
Lira-Ruan
D044002:Bryophyta / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D050901:Nitrate Reductase / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D017973:Tungsten Compounds / Q000494:pharmacology
D010940:Plant Proteins; D017973:Tungsten Compounds; D009569:Nitric Oxide; C025399:sodium tungstate(VI); D050901:Nitrate Reductase