The panorama of physiological responses and gene expression of whole plant of maize inbred line YQ7-96 at the three-leaf stage under water deficit and re-watering.

Changes in water potential, growth elongation, photosynthesis of three-leaf-old seedlings of maize inbred line YQ7-96 under water deficit (WD) for 0.5, 1 and 2 h and re-watering (RW) for 24 h were characterized. Gene expression was analyzed using cDNA microarray covering 11,855 maize unigenes. As for whole maize plant, the expression of WD-regulated genes was characterized by up-regulation. The expression of WD-regulated genes was categorized into eight different patterns, respectively, in leaves and roots. Newly found and WD-affected cellular processes were metabolic process, amino acid and derivative metabolic process and cell death. A great number of the analyzed genes were found to be regulated specifically by RW and commonly by both WD and RW, respectively, in leaves. It is therefore concluded that (1) whole maize plant tolerance to WD, as well as growth recovery from WD, depends at least in part on transcriptional coordination between leaves and roots; (2) WD exerts effects on the maize, especially on basal metabolism; (3) WD could probably affect CO(2) uptake and partitioning, and transport of fixed carbons; (4) WD could likely influence nuclear activity and genome stability; and (5) maize growth recovery from WD is likely involved in some specific signaling pathways related to RW-specific responsive genes.