Characterization of OsbZIP23 as a Key Player of the Basic Leucine Zipper Transcription Factor Family for Conferring Abscisic Acid Sensitivity and Salinity and Drought Tolerance in Rice  

OsbZIP23 is a member of the basic leucine zipper (bZIP) transcription factor family in rice (Oryza sativa). Expression of OsbZIP23 is strongly induced by a wide spectrum of stresses, including drought, salt, abscisic acid (ABA), and polyethylene glycol treatments, while other stress-responsive genes of this family are slightly induced only by one or two of the stresses. Transactivation assay in yeast demonstrated that OsbZIP23 functions as a transcriptional activator, and the sequences at the N terminus (amino acids 1-59) and a region close to the C terminus (amino acids 210-240) are required for the transactivation activity. Transient expression of OsbZIP23-green fluorescent protein in onion (Allium cepa)…