Isolation and deletion analysis of meristem specific promoter from <i style="">Sorghum bicolor</i> (L.) Moench.

Abstract

A meristem specific promoter of the S-phase specific gene (<i style="">cyc07)</i> has been cloned from <i style="">Sorghum bicolor </i>by polymerase chain reaction (PCR) using a proof reading DNA polymerase (Pfu polymerase). The 595 bp promoter consists of 2 repeats, a CAAT box and TATA box. The sequence was cloned in pBI 121 vector carrying the gene for b-D-glucuronidase (<i style="">GUS</i>) by replacing the 35S CaMV promoter. Transgenic tobacco plants were developed by <i style="">Agrobacterium</i>-mediated transformation and analyzed for tissue-specific expression. Incubation of kanamycin-resistant tobacco shoots with GUS substrate resulted in intense blue colouration in the shoot tips, root tips and root hairs proving that the promoter sequences were enough to induce meristem specific activity of the reporter gene. Four sequential deletions from the 5' end were carried out. The deletion analysis indicated that a 13 bp repeat I sequence was essential for regulation of meristem specific expression of the reporter gene.