- Kumar, P.A. et al. (1996). Adv Appl Microbiol 42: 1-43
- Parry, J. M. et al (1983). A Colour Atlas of Bacillus Species. Wolfe Medical, London.
- Schnepf, E. et al. (1998). Microbiol Mol Biol Rev 62: 775-806.
The insecticidal protein Cry I F of Bacillus thuringiensis is highly toxic to H. armigera in a synergistic manner with Cry 1 Ac. These crystalline proteins were found to be highly toxic to agriculturally important pests at very low concentrations. However, native Bt gene expression in plant cells is sub-optimal to achieve insect protection in transgenic plants because of the presence of many mRNA destabilizing features. Cloning of fragment 6th of synthetic cry 1 F was done with Vector (pGEM7Zf) while 4th and 5th fragments were cloned with pET vector after ligation (T4 DNA Ligase enzyme). These fragments were cloned with vector pGEM carrying 6th fragment. Now fragment 1+2+3 were assembled with pGEM7Zf carrying 4th, 5th and 6th fragments. A very good band of around 1900 bp was observed which is an indication of a positive clone. Now this pGEM 7Zf vector has all the six Cry 1 F synthetic fragments in between Xba 1 and Bam H1 sites. A modified Cry I F gene was designed according to higher plant codon usage and avoiding the mRNA destabilizing features. The modified gene has 45.5% of GC content.