Gene expression data from a pool of the four youngest leaves of Arabidopsis thaliana

● Adjustment to energy starvation is crucial to ensure growth and survival. In Arabidopsis thaliana (Arabidopsis), this process relies in part on the phosphorylation of the circadian clock regulator bZIP63 by SnRK1, a key mediator of responses to low energy. ● We investigated the effects of mutations in bZIP63 on plant carbon (C) metabolism and growth. Results from phenotypic, transcriptomic, and metabolomic analysis of bZIP63 mutants prompted us to investigate the starch accumulation pattern and the expression of genes involved in starch degradation and in the circadian oscillator. ● In order to get some clues about the role of transcription factor bZIP type bZIP63 in growth and development, we performed a comparative gene expression analysis of bzip63-2 mutant and wild type Ws, harvested at the end of night (EN = ZT 24), immediately before the onset of the light, to maximize the discovery of genes misregulated in bzip63-2. The resulting gene expression profiles revealed 230 upregulated and 117 downregulated genes in bzip63-2 compared to Ws. ● bZIP63 mutation impairs growth under light-dark cycles, but not under constant light. The reduced growth likely results from the accentuated C depletion towards the end of the night, which is caused by the accelerated starch degradation of bZIP63 mutants. The diel expression pattern of bZIP63 is dictated by both the circadian clock and energy levels, which could determine the changes in the circadian expression of clock and starch metabolic genes observed in bZIP63 mutants. ● We conclude that bZIP63 composes a regulatory interface between the metabolic and circadian control of starch breakdown to optimize C usage and plant growth. Three biological replicates of each genotype were used for microarray analysis, each replicate was composed of a pool of the four youngest leaves of five plants. Hybridization on the GeneChip Arabidopsis ATH1 array was done