Nitric oxide enhances plant ultraviolet-B protection up-regulating gene expression of the phenylpropanoid biosynthetic pathway

Publication Type:Journal Article
Year of Publication:2011
Journal:Plant, Cell & Environment
Date Published:2011
ISBN Number:1365-3040
Keywords:Arabidopsis, Cassia, flavonoids, HY5, maize, MYB12, ZmP

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.

Short Title:Plant, Cell & Environment
Fri, 2014-01-24 22:14 -- admin
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith