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

We have used a reverse transcriptase polymerase chain reaction procedure (differential display) to isolate cDNAs corresponding to transcripts that accumulate in ozone-treated Arabidopsis thaliana. In this report we describe the characterization of an ozone-induced transcript, AtOZI1. AtOZI1 mRNA in untreated plants was detected at low levels in cotyledons, leaves, and flower buds and at higher levels in roots and mature flowers. AtOZI1 mRNA accumulation was transiently induced in leaves 3- to 5-fold within the first 6 h of ozone treatment. AtOZI1 mRNA accumulation was also transiently induced 3- 6-fold by phytopathogenic Pseudomonas strains. Sequence analysis of AtOZI1 revealed that it encodes 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.