ICE1 regulation of the Arabidopsis Cold-Responsive Transcriptome

To understand the gene network that controls plant tolerance to cold stress, we carried out a near full genome transcript expression profiling in Arabidopsis using Affymetrix GeneChips that contain approximately 24,000 genes. For microarray analysis, Arabidopsis seedlings were cold treated at 0 C for 0 h, 3 h, 6 h, and 24 h. A total of 939 genes were statistically determined to be cold-regulated with 655 being up-regulated and 284 down-regulated. A large number of the early cold-responsive genes encode transcription factors that likely control late-responsive genes, which implies a multitude of transcriptional cascades. In addition, many genes involved in post-transcriptional and chromatin level regulation were also cold regulated suggesting their involvement in cold responsive gene regulation. A number of genes important for the biosynthesis or signaling of plant hormones, such as abscisic acid, gibberellic acid and auxin, are regulated by cold stress, which is of potential importance in coordinating cold tolerance with growth and development. We compared the cold-responsive transcriptomes of wild type and ice1, a mutant defective in an upstream transcription factor required for chilling and freezing tolerance. The transcript levels of many cold-responsive genes were altered in the ice1 mutant not only during cold stress conditions, but also before cold treatments. Our study provides a global picture of the Arabidopsis cold-responsive transcriptome and its control by ICE1, and thus will be valuable for understanding gene regulation under cold stress and the molecular mechanisms of cold tolerance. Keywords: Cold Stress response Two replicates for each time point of 0 hours, 3 hours, 6 hours and 24 hours of cold treatment for the wildtype (control) and ice1 (mutant).