ISOLATION OF A NOVEL ARABIDOPSIS OZONE-INDUCED CDNA BY DIFFERENTIAL DISPLAY

We have used a reverse transcriptase polymerase chain reaction procedu re (differential display) to isolate cDNAs corresponding to transcript s that accumulate in ozone-treated Arabidopsis thaliana. In this repor t we describe the characterization of an ozone-induced transcript, AtO ZI1. AtOZI1 mRNA in untreated plants was detected at low levels in cot yledons, leaves, and flower buds and at higher levels in roots and mat ure flowers. AtOZI1 mRNA accumulation was transiently induced in leave s 3- to 5-fold within the first 6 h of ozone treatment. AtOZI1 mRNA ac cumulation was also transiently induced 3- 6-fold by phytopathogenic P seudomonas strains. Sequence analysis of AtOZI1 revealed that it encod es a 8.6 kDa basic protein that contains a putative signal peptide and two potential phosphorylation sites. Our results suggest that AtOZI1 represents a novel stress-related protein that accumulates in response to the production of active oxygen species.