Co-expression analysis of dehydration stress response in Arabidopsis

ABA is a phytohormone that plays an essential role in dehydration stress responses, such as stomata closure, gene expression and stress tolerance. Many dehydration-inducible genes are regulated by ABA. In Arabidopsis ABA biosynthetic pathway, NCED3 (9-cis-epoxycarotenoid dioxygenase) was required for dehydration-inducible ABA accumulation that is essential for dehydration tolerance. In the present study, using transcriptome data of NCED3 knockout mutant (nc3-2) and wild type plants, we analyzed co-expressions of stress-inducible genes. We found 120 co-expression modules and focused on some modules in which stress-inducible genes were co-expressed. Co-expression analysis showed that the global gene-to-gene correlations occurred among ABA-regulated genes and JA-regulated genes. In ABA-regulated genes module, two cis-acting elements, ABRE and G-box, were significantly observed in their promoter regions. In JA-regulated genes module, many unknown motifs existed significantly in addition to ABRE and G-box. Co-expression analyses revealed new molecular mechanisms of dynamic gene networks in response to dehydration stress. We will also report network analysis of stress-repressed genes.