Promoters

The stress-inducible rd29A (responsive to dehydration 29A) promoter is derived from Arabidopsis thaliana, which is a small flowering plant that is a member of the mustard family (Brassicaceae). This promoter is responsive to drought, high-salinity and to the cold. From previous studies, the rd29A promoter not only increases the resistance to different stresses in plants, it also minimizes the negative effects such as plant growth reduction (only 30% grown reduction compared to the wild type plant and only a slight growth retardation phenotype on the tobacco plant ) in comparison to the 78% growth reduction of the 35S promoter. This proved that the rd29A is a better promoter than the 35S. Another study also showed that the survival rates of the transgenic clones (with the rd29A promoter) had a greater probability of survival for they recovered after exposure to freezing temperatures that was then returned to normal room temperature. This was compared to the non-transgenic that showed complete damage to the plant with no recovery from freezing. Therefore, the RD29A promoter is critically important for it can potentially improve agricultural techniques that farmers can use for their plants.

In our project, we designed the rd29A Promoter and the rd29A Promoter + Strong Plant Kozak (RBS) + RFP. These both came from the synthetic design that contained the rd29A Promoter + Strong Plant Kozak (RBS) + RFP in the pMA vector. The rd29A promoter was isolated by the use of the rd29A designed primers in PCR. This was blunt end Topo cloned, digested with EcoR 1 and Pst 1 sites, and was then ligated to the pSB1C3 vector. The design of the rd29A Promoter + Strong Plant Kozak (RBS) + RFP involved the ligation to the pSB1C3 vector using the EcoR 1 and Pst 1 sites. This composite part contains both the promoter and the reporter gene. This functions when the promoter is activated during environmental stress, which would then allow the expression of red fluorescence in plants that can be used as a warning signal to farmers that their plants are under stress.

References
Cong L, Zheng H, Zhang Y, Chai T. Arabidopsis DREB1A confers high salinity tolerance and regulates the expression of GA dioxygenases in Tobacco. Plant Science [serial online]. February 2008;174(2):156-164. Available from: Academic Search Premier, Ipswich, MA. Accessed October 24, 2010.
Babak B, Akira K, Fevziye C, Mie K, Kazuko Y, Kazuo W. Arabidopsis rd29A::DREB1A enhances freezing tolerance in transgenic potato. Plant Cell Reports [serial online]. August 26, 2007;26(8):1275-1282. Available from: Academic Search Premier, Ipswich, MA. Accessed October 25, 2010.