Differential expression of Arabidopsis defense-related genes in response to sulfur dioxide

摘要

Sulfur dioxide (SO_2) is one of the most common and harmful air pollutants. To analyze cellular responses to SO_2, we investigated the transcript alterations, antioxidant enzyme activities and reactive oxygen species (ROS) levels in Arabidopsis thaliana (Col-0) exposed to SO_2. Transcriptional profiling using Affymetrix GeneChip technology identified 494 genes differentially expressed ( -2-fold change) in plants exposed to 30 mg m~3 SO_2 for 72 h, including up-regulation of some defense-related genes encoding antioxidant enzymes and heat shock proteins. Moreover, numerous genes encoding pathogenesis-related proteins and enzymes required for the phenylpropanoid pathway and for cell wall modification were highly activated upon SO_2 exposure. We selected eight of the significantly differentially expressed defense-related genes for analysis using semi-quantitative RT-PCR and confirmed that their expression was up-regulated under SO_2 stress. In addition, SO_2 exposure caused the enhancement of ROS production, and also increased activities of antioxidant enzymes (superoxide dismutase, pcroxidase, glutathione peroxidase and glutathione S-transferase) in Arabidopsis plants. Our results indicated that increased ROS may act as a signal to induce defense responses, which provide enhanced defense capacity to protect plants against SO_2 and other environmental stress. This is the first transcriptional profiling that identifies novel genes and pathways involved in SO_2 stress responses in plant cells. These data will be helpful for better understanding the molecular basis for plant adaptation to SO_2 stress.