title: Nitric oxide enhances plant ultraviolet-B protection up-regulating gene expression of the phenylpropanoid biosynthetic pathway.
abstract: The link between ultraviolet (UV)-B, nitric oxide (NO) and phenylpropanoid biosynthetic pathway (PPBP) was studied in maize and Arabidopsis. The transcription factor (TF) ZmP regulates PPBP in maize. A genetic approach using P-rr (ZmP+) and P-ww (ZmP⁻) maize lines demonstrate that: (1) NO protects P-rr leaves but not P-ww from UV-B-induced reactive oxygen species (ROS) and cell damage; (2) NO increases flavonoid and anthocyanin content and prevents chlorophyll loss in P-rr but not in P-ww and (3) the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) blocks the UV-B-induced expression of ZmP and their targets CHS and CHI suggesting that NO plays a key role in the UV-B-regulated PPBP. Involvement of endogenous NO was studied in Arabidopsis nitric oxide dioxygenase (NOD) plants that express a NO dioxygenase gene under the control of a dexamethasone (DEX)-inducible promoter. Expression of HY5 and MYB12, TFs involved in PPBP regulation, was induced by UV-B, reduced by DEX in NOD plants and recovered by subsequent NO treatment. C4H regulates synapate esters synthesis and is UV-B-induced in a NO-independent pathway. Data indicate that UV-B perception increases NO concentration, which protects plant against UV-B by two ways: (1) scavenging ROS; and (2) up-regulating the expression of HY5, MYB12 and ZmP, resulting in the PPBP activation.
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC1245 (7600) Mar del Plata, Argentina.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Tossi
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC1245 (7600) Mar del Plata, Argentina.
authors.forename: Melina
authors.initials: M
authors.lastname: Amenta
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC1245 (7600) Mar del Plata, Argentina.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Lamattina
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC1245 (7600) Mar del Plata, Argentina.
authors.forename: Raúl
authors.initials: R
authors.lastname: Cassia
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects; D060387:Ascorbate Peroxidases; D053898:Biosynthetic Pathways / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D002374:Catalase / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects* / Q000528:radiation effects; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D010105:Oxygenases / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays; D015854:Up-Regulation / Q000187:drug effects* / Q000528:radiation effects; D003313:Zea mays / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects
chemical_list: D010636:Phenols; D010940:Plant Proteins; D009569:Nitric Oxide; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D010105:Oxygenases; C114415:nitric oxide dioxygenase