The regulation of 5′ upstream regions of a Korean radish cationic peroxidase gene by gibberellic acid and abscisic acid

The Korean radish cationic peroxidase promoter (KRPP) and the β -glucuronidase (GUS) gene were fused on the genome of tobacco BY-2 cells via Agrobacterium -mediated transformation method. A fragment of the KRPP comprising nucleotides −471 to +704 relative to the transcriptional initiation site confers constituent expression of GUS in transgenic tobacco BY-2 cells (BYK12). The expressed GUS activity was increased by as much as 40% at 577 nM gibberellic acid (GA 3 ). This increase was time and dose dependent. The abscisic acid (ABA) from 10 to 100 μM slowly decreased the GUS activity and at 100 μM reduced completely the inductive effect of GA 3 on GUS expression. Thus, GA 3 and ABA have antagonistic effects on the GUS expression mediated by the Korean radish cationic peroxidase promoter in transgenic BYK12 cells. Exogenous GA 3 activated the activity of the Korean radish isoperoxidases and also increased the intensity of two bands of Korean radish cationic isoperoxidases, when hypocotyl portions of the Korean radish seedlings grown in a green house for 10 days were examined using starch gel electrophoresis. However, ABA decreased the intensity of the Korean radish cationic isoperoxidase bands and also reduced the inductive effect of GA 3 in seedlings.