Cloning and functional analysis of the promoter of a stress-inducible gene (Zmap) in maize

The anionic peroxidases play an important role in a variety of plant physiological processes. We characterized and isolated the Zmap promoter (PZmap) at the 5′ flanking region in order to better understand the regulatory mechanisms of Zmap gene expression. A series of PZmap deletion derivatives, termed a1 –a6, at positions −1694, −1394, −1138, −784, −527 and −221 from the translation start site were blended to the β-glucuronidase reporter gene. Agrobacterium-mediated transformation method was used to study each deletion construct in tobaccos. Sequence analysis showed that several cis-acting elements (MYB binding site, Box-II, a TGACG-element, a CGTCA-element and a low temperature responsive element) were located within the promoter. Deletion analysis suggested the sequence between −1,694 and −1394bp may contain cis-elements associated with GUS up regulation. The MYB binding site (-757) might act as a negative drought-responsive element. There might be repressor elements located in the region (−1,694 to −1394bp) to repress Zmap expression under 4°C. The characterized promoter would be an ideal candidate for genetic engineering for improving the resistance of maize to different stressors.