ATAF1, an Arabidopsis thaliana NAC transcription factor, plays important roles in plant adaptation to environmental stress and development. To search for ATAF1 target genes, we used protein binding microarrays and chromatin-immunoprecipitation (ChIP). This identified T[A,C,G]CGT[A,G] and TT[A,C,G]CGT as ATAF1 consensus binding sequences. Co-expression analysis across publicly available microarray experiments identified 25 genes co-expressed with ATAF1. The promoter regions of ATAF1 co-expressors were significantly enriched for ATAF1 binding sites, and TTGCGTA was identified in the promoter of the key abscisic acid (ABA) phytohormone biosynthetic gene NCED3. ChIP-qPCR and expression analysis showed that ATAF1 binding to the NCED3 promoter correlated with increased NCED3 expression and ABA hormone levels. These results indicate that ATAF1 regulates ABA biosynthesis.
Keywords: ABA, abscisic acid; ATAF1, Arabidopsis thaliana activating factor 1; Abscisic acid biosynthesis; Arabidopsis; ChIP, chromatin-immunoprecipitation; DBD, DNA-binding domain; DNA-binding; NAC transcription factor; NAC, NAM, ATAF1/2, CUC2; NCED3, 9-cis-epoxycarotenoid dioxygenase-3; PBM, protein-binding microarrays; PWM, position weight matrix; SnRK, Sucrose nonfermenting 1(SNF1)-related serine/threonine-protein kinase; TF, transcription factor.