EN
High ozone concentration generates oxidative stress in plants. To investigate the detailed transcriptional regulation of Arabidopsis thaliana genes encoding antioxidant enzymes upon ozone stress, we performed a microarray analysis using Affymetrix GeneChip technology. Our transcription profiling revealed a differential expression equal or greater than 2-fold change for 2385 genes (at confidence 99%) in response to 350 ppb ozone dose after 3 and 6 hours of treatment. Among these, we chose 38 genes to be oxidative stress related in ozone treatment: 29 of them were 2 times up-regulated and 9 were shown to be down-regulated in at least one of the time points. Our study revealed a new transcription pattern for catalase genes and showed the first detailed transcriptional analysis of phenylopropanoid-related genes in ozone stress conditions.