Abstract
ABA is a phytohormone that plays an essential role in dehydration stress response. Many of dehydration inducible genes are regulated by ABA signal. There are 6 genes encoding a 9-cis-epoxycarotenoid dioxygenase (NCED), a key enzyme involved in the biosynthesis of ABA in Arabidopsis genome. Among the 6 NCEDs, NCED3 is involved in dehydration-inducible ABA accumulation that is essential for dehydration tolerance. In the present study, using NCED3 knockout mutant (nc3-2), we analyzed the ABA-dependent transcriptome and metabolome in response to dehydration stress. Transcriptome analysis showed that ABRE and AREB/ABF are major cis- and trans-acting factors, respectively, in ABA-dependent gene expression in the dehydration-stress response. Co-expression analysis also showed the global gene-to-gene correlations occurred in ABA-regulated genes. Integration of metabolomics and transcriptomics analyses revealed new molecular mechanisms of dynamic metabolic networks in response to dehydration stress. Endogenous ABA plays an essential role in these processes.